v2.1.30: Several fixes, see matching milestone

Version 2.1.30

Important! build.less file name has been been changed to
bootstrap-datetimepicker-build.less to prevent collisions

Fix for #135: setStartDate and setEndDate should now properly set.
Fix for #133: Typed in date now respects en/disabled dates
Fix for #132: En/disable picker function works again
Fix for #117, #119, #128, #121: double event change event issues should
be fixed
Fix for #112: change function no longer sets the input to a blank value
if the passed in date is invalid

Enhancement for #103: Increated the z-index of the widget