* Update doxygen docs with new smartSleep behavior
* Update docs to new behavior.
* Add info on how to set wait time in smartSleep.
* Fix incorrect docs regarding return value of smartSleep.
* Update docs for return value of all sleep methods
* Clarify the return value of the sleep methods, suggested by
@mfalkvidd.
* Make smartSleep send heartbeat before sleeping
Sending the heartbeat (and waiting) after waking up would delay
processing inputs. For example, a switch could be back to the
open state before the wait is over.
* Fix typos in comments in smartSleep methods
Martin Hjelmare