Common styles file added

Common pieces of code should be placed in this file
Navigation improvements: generated from json, styles updates

Added _harp.json file to store all common data in it
Rename: font.less to typography.less
Update README harp instructions to use public directory
Add hero partial

Implement typography partials

Complete Adobe Sourse Sans Pro typography partial
Add back-to-top shared partial

Add tech-details typography partial
Merge branch 'typography' of https://github.com/MunGell/wallhack into typography