ddllib: Introducing create_temp_table()

ddllib: Introducing create_temp_table()

Close sibling to create_table() - will create a temporary table.
Two aspects of its usage are interesting

 - you _must_ truncate the table after creation as you may be
   "inheriting" an existing temp table from the former user
   of your persistent connection

 - you must use the tablename returned to support MSSQL and any
   other DB that needs special names for temp tables

A couple of TODOs

 - I just don't know how to actually munge the tablename for MSSQL
   (help! Eloooooyyyy!)

 - Surely Eloy will have something better than the preg_replace() ;-)