Make skip link look less "bare bones"

BS3 commits: d5647e1f6277864cb776e4f958a54f6f5c30b6e6
Expand/clarify advice about skip links

BS3 commits: 2d41894ce51a1ae3b6e9d96eb63bf9cc3b50f64b
Correction in the documentation, add the brand-primary true color in comment and woff2 glyphicons

BS3 commits: b7be72c86c9b8b0289438f5e97a2263ecdb1344c
grunt