This mod adds a checksum function to topic/reply posting, in order to eliminate duplicate posts due to browser back button presses, server lags, etc.

Edited since I left a piece of code out ... and a second time since I neglected to consider a duplicate reply to a different topic.

v1.1 Reduced the size of the checksum field to 16 - and changed the select statements to only get what is needed.

v2.0 Added chksum to archive table, thanks to those who pointed it out.