Merge in changes from my cdr-tds-conversion branch. This changes the internal

implementation from using the volatile libtds, to using the db-lib front end.
The unintended side effect of this is that we support (at least) versions 0.62
through 0.82 of the FreeTDS distribution without any #ifdef ugliness.

(closes issue #12844)
Reported by: jcollie


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@126226 65c4cc65-6c06-0410-ace0-fbb531ad65f3