Fixed bug when removing items

Found this bug:

Say you have the array ['Yes', 'No']

Calling tagsinput('remove', 'Maybe') would cause an element to be removed, although no match was found. This is because $.inArray returns -1 if the item isn't found, and we then splice between -1 and 1.
Merge branch 'patch-1' of https://github.com/soroushhakami/bootstrap-tagsinput into soroushhakami-patch-1
Merge branch 'soroushhakami-patch-1'