** fix for #437 **

-> Fixed a bug when the data-label attribute is used on the original select. It was conflicting with the custom function called "label(element)" and overriding it.
Renamed label() to getLabel()
Merge branch 'fix_#437' of https://github.com/Tyf0x/bootstrap-multiselect into Up-To-Date
** Unit-test update **

-> Fixed a failure on test for #405 due to the code changes
Merge branch 'fix_#431' of https://github.com/Tyf0x/bootstrap-multiselect into shift-select-improvement
Merge branch 'shift-select-improvement' of https://github.com/Tyf0x/bootstrap-multiselect into Up-To-Date