Tweak side nav styles
Use `.form-control` in input sizing CSS
Update inline and horizontal forms

* No more need for `.row.form-group`--only need `.form-group`
* Change tag selectors for inline form to use `.form-control`
* Docs improved to explain what's happening
Ignore less dir in Jekyll
Simpler horizontal form button placement
Fixes #8293: sub nav links in JS docs
Merge branch '3.0.0-wip' of github.com:twitter/bootstrap into 3.0.0-wip