fixes dead links in tutorials

fixes #595 or at least the dead links that are in the tutorials

Author: twisst

content/tutorials/text/images-and-pixels/index.mdx

@@ -206,8 +206,8 @@ updatePixels();
 
 First, we should point out something important in the above example. Whenever you are accessing the pixels of a Processing window, you must alert Processing to this activity. This is accomplished with two functions:
 
-- [loadPixels()](http://processing.org/reference/loadPixels_.html) This function is called before you access the pixel array, saying "load the pixels, I would like to speak with them!"
-- [updatePixels()](http://processing.org/reference/updatePixels.html) This function is called after you finish with the pixel array saying "Go ahead and update the pixels, I'm all done!"
+- [loadPixels()](https://processing.org/reference/loadPixels_.html) This function is called before you access the pixel array, saying "load the pixels, I would like to speak with them!"
+- [updatePixels()](https://processing.org/reference/updatePixels_.html) This function is called after you finish with the pixel array saying "Go ahead and update the pixels, I'm all done!"
 
 In the above example, because the colors are set randomly, we didn't have to worry about where the pixels are onscreen as we access them, since we are simply setting all the pixels with no regard to their relative location. However, in many image processing applications, the XY location of the pixels themselves is crucial information. A simple example of this might be, set every even column of pixels to white and every odd to black. How could you do this with a one dimensional pixel array? How do you know what column or row any given pixel is in?
 
@@ -223,7 +223,7 @@ In programming with pixels, we need to be able to think of every pixel as living
 
 </FixedImage>
 
-This may remind you of our [two dimensional arrays tutorial](http://www.processing.org/learning/2darray/). In fact, we'll need to use the same nested for loop technique. The difference is that, although we want to use for loops to think about the pixels in two dimensions, when we go to actually access the pixels, they live in a one dimensional array, and we have to apply the formula from the above illustration.
+This may remind you of our [two dimensional arrays tutorial](https://processing.org/tutorials/2darray). In fact, we'll need to use the same nested for loop technique. The difference is that, although we want to use for loops to think about the pixels in two dimensions, when we go to actually access the pixels, they live in a one dimensional array, and we have to apply the formula from the above illustration.
 
 Let's look at how it is done.
 

content/tutorials/text/pvector/index.mdx

@@ -118,7 +118,7 @@ Here are some vectors and possible translations:
 
 </FixedImage>
 
-You've probably done this before when programming motion. For every frame of animation (i.e. single cycle through Processing's (http://processing.org/reference/draw_.html)draw()] loop), you instruct each object on the screen to move a certain number of pixels horizontally and a certain number of pixels (vertically).
+You've probably done this before when programming motion. For every frame of animation \(i.e. single cycle through Processing's [draw\(\) loop](http://processing.org/reference/draw_.html)\), you instruct each object on the screen to move a certain number of pixels horizontally and a certain number of pixels (vertically).
 
 For a Processing programmer, we can now understand a vector as the instructions for moving a shape from point A to point B, an object's &ldquo;pixel velocity&rdquo; so to speak.
 

content/tutorials/text/strings-and-drawing-text/index.mdx

@@ -43,7 +43,7 @@ Clearly, this would be a royal pain in the Processing behind. It's much simpler
 String sometext = "How do I make String? Type some characters between quotation marks!";
 ```
 
-It appears from the above that a String is nothing more than a list of characters in between quotes. Nevertheless, this is only the data of a String. We must remember that a String is an object with methods (which you can find on the reference page.) This is just like how we learned in the [Pixels tutorial](http://processing.org/learning/pixels/) that a [PImage](http://processing.org/reference/PImage.html) stores both the data associated with an image as well as functionality: [copy()](http://processing.org/reference/copy_.html), [loadPixels()](http://processing.org/reference/loadPixels_.html), etc.
+It appears from the above that a String is nothing more than a list of characters in between quotes. Nevertheless, this is only the data of a String. We must remember that a String is an object with methods (which you can find on the reference page.) This is just like how we learned in the [Pixels tutorial](https://processing.org/tutorials/pixels) that a [PImage](http://processing.org/reference/PImage.html) stores both the data associated with an image as well as functionality: [copy()](http://processing.org/reference/copy_.html), [loadPixels()](http://processing.org/reference/loadPixels_.html), etc.
 
 For example, the method [charAt()](http://processing.org/reference/String_charAt_.html) returns the individual character in the String at a given index. Note that Strings are just like arrays in that the first character is index #0!
 
@@ -329,7 +329,7 @@ In addition to textAlign() and textWidth(), Processing also offers the functions
 
 ## Rotating text
 
-[Translation and rotation](http://processing.org/learning/transform2d/) can also be applied to text. For example, to rotate text around its center, translate to an origin point and use `textAlign(CENTER)` before displaying the text.
+[Translation and rotation](https://processing.org/tutorials/transform2d) can also be applied to text. For example, to rotate text around its center, translate to an origin point and use `textAlign(CENTER)` before displaying the text.
 
 [Example: Rotating Text](http://learningprocessing.com/examples/chp17/example-17-05-rotatetext)