Remove PinoccioScout::delay

It didn't actually do anything anymore, but it was still used bye
PinoccioScout::setup (but before setting up the serial port, so the
warning message was lost). By removing this method, that call falls back
to using the global function delay() again, as you'd expect.
Add 'power.hibernate' function to put the scout to sleep

This function disables the mesh networking and as much hardware as
possible and puts the chip into "deep sleep".

It uses timer2, controlled by the 32khz clock to schedule the wakeup. If
any other interrupt occurs in the meanwhile, the hibernate could be cut
short (but most other interrupts are not able to actually wake up the
scout from deep sleep).

After the hibernate is complete, an optional callback bitlash function
is called.

Going into hibernation does not yet disable any backpacks and leaves the
backpack vcc on. Serial communiation might be cut off halfway through a
byte, this should be improved later.
Add scout.walltime, .cputime and .sleeptime

cputime gives the time the CPU clock has been running, in milliseconds.
sleeptime approximates the amount of time the CPU has been hibernating.
walltime simply adds these two.
Merge sleep
Remove memory from uptime report post sleep merge