Add a "devstate change" CLI command to control custom device states. Also,

do some additional code cleanup and improvement in passing.

(closes issue #12106)
Reported by: nizon
Patches:
      devstate-patch.txt uploaded by nizon (license 415)
        -- Updated to trunk, and tab completion added by me


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@105461 65c4cc65-6c06-0410-ace0-fbb531ad65f3