Mark3 RTOS Source

- Breaking timerlist into separate timer/timerscheduler/timerlist modules
- removing underscores from filenames in kernel for consistency
- renaming kprofile to kernelprofile for consistency
- Adding mark3.h, which wraps all kernel objects/APIs with a single include
- Refactoring Arduino support so that importing the Mark3 lib results in only "mark3.h" being included, instead of every kernel header

-Cleaning up a bunch of doxygen warnings in the kernel code
-Taking middleware out of the main docs. It's way too much for one volume; will create volumes for middleware code later.

flAVR doesn't support EEPROM operations quite yet -- switching high-score mechanism in Super Brick Break to use RAM for high-scores until then.

--Adding kernel-aware simulator joystick driver
--Adding kernel-aware API to allow the application to detect that it's being simulated by a kernel-aware simulator
--Simplifying bitmap API to avoid colorspace conversion for speed/size.
--Updating Super Brick-Breaker example to use mark3 kernel-aware joystick plugin

Adding breakout clone to example code

Adding basic joystick and PWM sound generator for atmega328p

--Adding rudimentary flAVR co-simulated graphics driver support.

Removing the deprecated export_arduino.sh script, as it's no longer used. export.sh now has a special arduino target.

Fixing the generic cortex M0 port to use the correct Critical Section & interrupt enable/disable logic. Verified on SAMD20.

Updated generic ARM Cortex-M0 port with instructions on where to add part-specific #includes.
Replaced all uses of K_UCHAR for booleans with standard bool