merge in new ads
fixes #10961: change variable names in grid docs
Merge branch 'master' of github.com:twbs/bootstrap
fix #10961
update gitignore to restore the ruby-version ignore and rename section to all docs stuff
Merge branch 'master' of github.com:twbs/bootstrap

Conflicts:
	css.html
document .h1 thru .h6; fixes part of #10102
Merge pull request #10962 from twbs/doc-h1-thru-h6-classes

document .h1 thru .h6; fixes part of #10102
run grunt
Fixes #10959: round the .lead values down to nearest pixel via floor()
Merge branch 'master' of github.com:twbs/bootstrap
Half fix for #9855: Don't fuck with margins for open modal dialog on account of Lion non-scrollbars and inconsistencies elsewhere
Fixes #10126: Update responsive test cases to properly highlight hidden class examples