Bcmxcp advanced functions

Added more variables (battery packs count, sleep mode, beeper control etc.). 
Added function which request list of settable variables.
Added indication of ABM status for internal batteries.
Added outlet control (immidiate shutdown, turn on)/
outlet.n.shutdown.return now wait shutdown_delay time, not outlet.n.delay.shutdown because not all firmware accept it, so shutdown time will be -1 which is wrong.

Tested on pw 5125.