4.0.2 Add constants to turn off msgs (BT,cgm,phne)

Added additional documentation to constants to make it easier to change
Added ranges to constants documentation
Moved message timers our of documentation
Merge pull request #24 from YYGIRL/4.0.2

4.0.2 Add constants to turn off msgs (BT,cgm,phne)
Merge pull request #1 from nightscout/master

Merge into master