core: renamed MCU section variable name

This was clashing with the command register

Signed-off-by: Michel Pollet <buserror@gmail.com>
cores: m16 and m32 fix

Core struct declaration had a problem when the 'porta' was not declared.
Now declare it last, so it doesnt clash anymore.
Correctly set timer1's ICP on atmega8, atmega16 and atmega32.
Merge pull request #37 from ppd1990/atmega-icp

Correctly set timer1's ICP on atmega8, atmega16 and atmega32.
Fix timer0 on megax MCUs. Stick to lowest common denominator (atmega8) in terms of functionality.
Merge pull request #38 from ppd1990/megax-timer

Fix timer0 on megax MCUs. Stick to lowest common denominator (atmega8) i...
correct a segfault
fix typo
Merge pull request #42 from nnayo/typo

fix typo
Merge pull request #41 from nnayo/segfault

correct a segfault
Extend special_init/special_deinit API

Its pretty common for callback style APIs to include a private pointer
to allow the user to pass in contextual data through the callback API
(see pthread_create for an example). This change adds that for
special_init() and special_deinit() which are designed as callbacks.
Effectively this behavior was used in the only two examples that used
those callbacks by having global variables, however globals are of
limited use for programs that might instantiate multiple avr cores.
Merge pull request #43 from cardoe/special-init-api

Extend special_init/special_deinit API