Fix some bugs in CDRs; add some CLI commands to help debugging

This patch fixes a few minor bugs and one major one: the CDR by bridge
container was less than helpful. The mechanism previously used to try
and find all of the CDRs in a particular bridge ended up missing CDRs,
resulting in incorrect records.

When looking up CDRs in a bridge, we now just bite the bullet and do
a selection across all existing CDRs.

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@393599 65c4cc65-6c06-0410-ace0-fbb531ad65f3