Bump Jekyll to v2.5.1.

BS3 commits: 1764c6e5090a687f3a3f3fc4a8ee595eea22a03f
grunt
darken primary blue for accessibility contrast on link colors

BS3 commits: eb74a8cbf363699eb822057650ddff2f36765ec9
Glyphicon accessibility tweaks

BS3 commits: 5339f7c8d577f5890f324df2a9310d7c1f1cb2bd
Update devDependencies.

BS3 commits: 7047f9df14d89c9b38bff2d76be5c1d5f0f2b5db
Run `grunt`.

BS3 commits: bf4a331f1a6817b477bd5a931bb3b0671997f9de
grunt. darken primary blue for accessibility contrast on link colors. Run `grunt`.

BS3 commits: d1278efcc5a6b45467caca15206bb1a83ae99fc5,
eb74a8cbf363699eb822057650ddff2f36765ec9,
bf4a331f1a6817b477bd5a931bb3b0671997f9de
darken primary blue for accessibility contrast on link colors

BS3 commits: eb74a8cbf363699eb822057650ddff2f36765ec9
grunt. darken primary blue for accessibility contrast on link colors

BS3 commits: d1278efcc5a6b45467caca15206bb1a83ae99fc5,
eb74a8cbf363699eb822057650ddff2f36765ec9