simplify type.less
Dustin the docs again

* Fix alllll the links!
* Change all `*.js` in JS plugin docs (no mo `bootstrap-`)
* Fully remove `tr.info`
* Bring nav includes up to date
Merge pull request #8430 from juthilo/3.0.0-docs-fixes

Dustin the docs again
Merge pull request #8426 from liuyl/simplify-type

simplify type.less
rename .retina-image => .img-retina
Update forms.less

All variables should be set in variables.less?
rm .control-group from docs since it's no longer in the LESS
Merge pull request #8455 from cvrebert/control-group-dead

rm .control-group from docs since it's no longer in the LESS
Merge pull request #8454 from bassjobsen/patch-2

Update forms.less
Merge pull request #8453 from cvrebert/retina-rename

rename .retina-image => .img-retina
Merge pull request #2 from twitter/3.0.0-wip

3.0.0 wip