Unbind values of fields which inserted directly in sql query (if need to update many fields).

My last update for PDOWrapper class was usefull for updating integer fields by way of incrementing in sql query. So I found the problem: if need to update many fields (not only one, which has to be incremented) - query does not work. I've solved this problem by unsetting fields which inserted directly into query from bind array and query works now. Merge this fix, please.