Add hw_config_avr.hpp .
Move MSP430-specific headers to a subdir.
Update msp430 header paths.
Move AVR-specific headers to a subdir.
Update AVR header paths.
Move Cortex-M-specific headers to a subdir.
Update Cortex-M header paths.
Move LM4-specific headers to a subdir and renamed to TM4.
Update TM4 header paths.
Move STM32-specific headers to a subdir.
Move EFM32-specific headers to a subdir.
Remove stm32-libopencm3 completely (no resources to maintain).
Rename lm4 target to tm4.
Fix write_bit() return type.
Update for ITimer param refactor.
Actually return value from read().
Convert lcd example to hw_config.
Add hd44780 bus config for msp430.
Implement AVR dynamic delay.
Implement AVR CPU enable/disable irqs.