refactor sleep and loop

[jacobrosenthal]

We were keeping sleep state in several different places
sleepUntilMatch could return a boolean locally which was unused
local state was actually held in timer_match
then scheduledticks could be called to return if there were ticks left

Ive collapsed these keeping the timer_match as the internal class state variable.
For external scheduledticksleft() still exists, but is returned from dosleep so should never need to be called

The result is that scout can simplify sleepPending handling greatly.

Besides being better, I think Ill be persuing a state machine instead of booleans to control sleep state especially as I look at adding radio sleep to synchronize between scouts.

also theres a bunch of led indication stuff cluttering up the loop Id like to move out to an led handling function