fix filterBehavior both
Fixed the error "Cannot read property 'is' of undefined " when applying "includeSelectAllOption" and "includeSelectAllDivider" options
Merge pull request #256 from yuripc/patch-1

Fix filterBehavior 'both'.
Merge pull request #259 from hermanho/master

Fixed the error "Cannot read property 'is' of undefined " when applying ...
#270, #263, #260, #262, #261, #235. New option: includeSelectAllIfMoreThan. Fixed issues with select all and dividers. Updated documentation concerning show/hide event.
Merge branch 'master' of https://github.com/davidstutz/bootstrap-multiselect, fixed select all.

Conflicts:
	js/bootstrap-multiselect.js