Restore missing CSS into less sources

This restores CSS rules that are present in the bundled `main.min.css`, but missing from the `*.less` sources. It also fixes the icomoon glyphs for GitHub, Twitter and so on. It's a bit hacky, but this is a stopgap for #1 so I can start use the theme (which I :heart:) but customize some of the colors.

Note that this doesn't get you *quite* to the point where a `grunt` execution causes no changes to the git status. `imagemin` still optimizes some of the images and there are a few minor CSS and JS differences remaining, mostly trivial ordering differences. Here's the full list:

```bash
smash@winter ~/code/Jekyll-HMFAYSAL-V2-Theme (restore-missing-styles=) $ git status
# On branch restore-missing-styles
# Changes not staged for commit:
#   (use "git add <file>..." to update what will be committed)
#   (use "git checkout -- <file>..." to discard changes in working directory)
#
#	modified:   assets/css/main.min.css
#	modified:   assets/js/scripts.min.js
#	modified:   images/Jekyll-HMFAYSAL-Theme.jpg
#	modified:   images/KY-Nailing-Machine.jpg
#	modified:   images/apple-touch-icon-114x114-precomposed.png
#	modified:   images/apple-touch-icon-144x144-precomposed.png
#	modified:   images/apple-touch-icon-72x72-precomposed.png
#	modified:   images/apple-touch-icon-precomposed.png
#	modified:   images/bio-photo.jpg
#	modified:   images/default-thumb.png
#	modified:   images/texture-feature-01.jpg
#	modified:   images/texture-feature-02.jpg
#	modified:   images/texture-feature-03.jpg
#	modified:   images/texture-feature-04.jpg
#	modified:   images/texture-feature-05.jpg
```