Add Util\Arrays::unsetAll
Add Util\Arrays::nullifyEmptyStrings
Merge pull request #43 from chadicus/master

unsetAll(), nullifyEmptyStrings

unsetAll is a convenience method that will remove all elements specified by the $keys array.

nullifyWhiteSpace will convert all strings containing only whitespace to null. Usefull for db inserts when you want to insert null and not an empty string.