This change permits each verbose destination (consoles, logger) to have its
own concept of what the verbosity level is.  The big feature here is that
the logger will now be able to capture a particular verbosity level without
condemning each console to need to suffer that level of verbosity.
Additionally, a stray 'core set verbose' will no longer change what will go
to the log.

Review:  https://reviewboard.asterisk.org/r/1599/


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@355413 65c4cc65-6c06-0410-ace0-fbb531ad65f3