Gitlab is a popular Git repository manager using an opensource license.
This commit adds the Gitlab social icon.

2.0 Enhancements

- Improve template structure
- Fixed issue where flexbox was configured improperly and the side column expanded with longer content.
- No longer assume that posts are called "post"
- Simplify tag handling
- Improve related posts handling
- Support native Table of contents (if declared in params)
- Add DISQUS commenting (if disqusShortname added to config)
- Uses Hugo's Related content feature 
- Add asset hashing to Webpack for performance

Fixes #70

* add linkedin

* update github svg to fix spacing

* add colors from brandcolors.net

* add github social link

* add github css

* fix css error breaking rollover