At the request of ManxPower, include the UPGRADE.txt from 1.2 and 1.4, as well.

This way, if people need to go back and review what was deprecated in previous
major releases, it is readily available to them.  Thanks for the suggestion!


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@103044 65c4cc65-6c06-0410-ace0-fbb531ad65f3