Fix for #4550

Also fixes dropdowns hiding behavior for case when two or more dropdowns
with [data-toggle=dropdown] exist on the page
Merge pull request #5323 from artiz/master

Please check my fix for #4550
Merge remote-tracking branch 'twitter/bootstrap/master'
Update version number of built files
Finish the grid system
Merge branch 'master' of github.com:aredridel/bootstrap.stylus