Some updates to README (#158)

* Remove obsolete website reference

@steffennissen's domain leenissen.dk seems to have been taken over by
some Thai domain squatter in 2024 (see
https://punktum.dk/domaene/ikke-tilg%C3%A6ngelig?domain=leenissen.dk)
and now contains only some sloppy and shallow texts about FANN.

* Add section about precompiled packages

* reference repology package status
* detail Debian package names and installation command

* Fix whitespace & use consistent command markup

Author: mikini

README.md

@@ -3,11 +3,11 @@
 
 **Fast Artificial Neural Network (FANN) Library** is a free open source neural network library, which implements multilayer artificial neural networks in C with support for both fully connected and sparsely connected networks.
 
-Cross-platform execution in both fixed and floating point are supported. It includes a framework for easy handling of training data sets. It is easy to use, versatile, well documented, and fast. 
+Cross-platform execution in both fixed and floating point are supported. It includes a framework for easy handling of training data sets. It is easy to use, versatile, well documented, and fast.
 
-Bindings to more than 15 programming languages are available. 
+Bindings to more than 15 programming languages are available.
 
-An easy to read introduction article and a reference manual accompanies the library with examples and recommendations on how to use the library. 
+An easy to read introduction article and a reference manual accompanies the library with examples and recommendations on how to use the library.
 
 Several graphical user interfaces are also available for the library.
 
@@ -40,22 +40,32 @@ Several graphical user interfaces are also available for the library.
 
 First you'll want to clone the repository:
 
-`git clone https://github.com/libfann/fann.git`
+    git clone https://github.com/libfann/fann.git
 
 Once that's finished, navigate to the Root directory. In this case it would be ./fann:
 
-`cd ./fann`
+    cd ./fann
 
 Then run CMake
 
-`cmake .`
+    cmake .
 
 After that, you'll need to use elevated privileges to install the library:
 
-`sudo make install`
+    sudo make install
 
 That's it! If everything went right, you should see a lot of text, and FANN should be installed!
 
+#### From Distribution Packages
+
+Many Linux distributions carry precompiled FANN packages in their binary repositories.
+
+See Repology for further information: [![Packaging status](https://repology.org/badge/tiny-repos/fann.svg)](https://repology.org/project/fann/versions).
+
+On Debian derived distributions install the package [libfann2](https://packages.debian.org/search?searchon=names&keywords=libfann2) and potentially [libfann-dev](https://packages.debian.org/search?searchon=names&keywords=libfann-dev) if you desire to develop for the library. Fx. by issuing the following command in a root terminal:
+
+    apt install libfann2 libfann-dev
+
 ### Building fann - Using vcpkg
 
 You can download and install fann using the [vcpkg](https://github.com/Microsoft/vcpkg) dependency manager:
@@ -67,9 +77,3 @@ You can download and install fann using the [vcpkg](https://github.com/Microsoft
     ./vcpkg install fann
 
 The fann port in vcpkg is kept up to date by Microsoft team members and community contributors. If the version is out of date, please [create an issue or pull request](https://github.com/Microsoft/vcpkg) on the vcpkg repository.
-
-## To Learn More
-
-To get started with FANN, go to the [FANN help site](http://leenissen.dk/fann/wp/help/), which will include links to all the available resources. 
-
-For more information about FANN, please refer to the [FANN website](http://leenissen.dk/fann/wp/)