Mark3 RTOS Source

Cleaning up tabs. Making sure that cortex m3/m4 files are not misrepresented as cortex m0 in the headers. Documentation for those ports needs more work, however.

- Adding preliminary cortex m4-f support
- Fixing usage of isb in cortex ports for control register modification
- Fixing demo stack-size usage in thread init.

- Cleaning up cortex m0 + m3 ports.
- Optimize context switching for m3 and up, which has a more capable ldmia/stmia.

-Ensure that the official test suite is only built for AVR, and not for other architectures where support for kernel-aware debugging, and built-in drivers may not exist.

Improvements to preliminary cortex m3/4/7 port.

- Removed superfluous code that was brought in out of desparation yesterday
- Cleaning up stuff, now that I know the fundamental code works
- Fixing linker args correctly so that "undefined reference to 'x'" doesn't occur

Adding rough kernel setup example for cortex m3

Adding very-rough prototype cortex M3/4/7 support to the kernel

Adding support for assembly-language objects.

Adding preliminary circular-buffer based stream class

Fixing scheduler to use correct defines from mark3cfg.h instead of scheduler.h for determining number of thread priorities.