Hamburger-box vertical align middle SCSS/CSS fix

Hi @jonsuh,

I want to make a small suggestion on the styling of hamburgers.

To be precise, the .hamburger-box has display: inline-block, which is good. But it's missing: vertical-align: middle;. I suggest adding this to the styling.

Not that it is not possible to add this yourself additionally. But it saves everyone an extra line. I think you will make a lot of people happy with this change.

hamburgers/_sass/hamburgers/_base.scss

On line 51.

.hamburger-box {
  width: $hamburger-layer-width;
  height: $hamburger-layer-height * 3 + $hamburger-layer-spacing * 2;
  display: inline-block;
  vertical-align: middle;
  position: relative;
}

hamburgers/dist/hamburgers.css

On line 35

.hamburger-box {
  width: 40px;
  height: 24px;
  display: inline-block;
  vertical-align: middle;
  position: relative; }

Thank you for your great work, this repo takes the websites we build to the next level!

Cheers!

[Alessandro-Battiato]

Opened a PR! Let me know if the changes I made are exactly what you asked for