Fixes #14440: Remove unused nav variable

BS3 commits: f265137c0517266206055d306ed41e9456878652
README.md: Change links to use HTTPS

BS3 commits: e3c26407827794df917f6d2d0f378cb5bf7f39e8
fixes 14441

BS3 commits: 28c907f635bf4f3413c5ae641773b0cf38e80672
fixes 14425: remove invalid css property

BS3 commits: 3c0e2e28f8c421c3e96ff39da2a088410fffff45
Fixes 14386: Reset font, text, and line-height properties in popovers

BS3 commits: 56bb92ac4fbf6d5773e91afd205fb8ec09e3a573
Full grunt

BS3 commits: 32a6d9b404751b343f9043bdf48b67295b0dbebc
grunt. grunt. Full grunt. grunt

BS3 commits: 6a0eb4e6bd19c5a9ddd201fbd2accca54f9a7dc9,
4fc96e802950cb7fe9aa0580203992f2c467afe5,
32a6d9b404751b343f9043bdf48b67295b0dbebc,
0140198699a41d299cd2d100e01c12c967b765e4
grunt. grunt

BS3 commits: 6a0eb4e6bd19c5a9ddd201fbd2accca54f9a7dc9,
4fc96e802950cb7fe9aa0580203992f2c467afe5
Fixes 13943 again: lighten links, and text, in navbar. Still not 100% compliant, but it's better. grunt. Fixes 14386: Reset font, text, and line-height properties in popovers. Full grunt. grunt

BS3 commits: 9a39ee90b4fd4d5b9b6f9a6f2c9d5a29ffeafe92,
4fc96e802950cb7fe9aa0580203992f2c467afe5,
56bb92ac4fbf6d5773e91afd205fb8ec09e3a573,
32a6d9b404751b343f9043bdf48b67295b0dbebc,
0140198699a41d299cd2d100e01c12c967b765e4
Update link to Run Jekyll on Windows guide

BS3 commits: 1517bea4e272935a31fdc0caaa9a924bb8346ca3