Add AVR UART implementation.
Add missing include.
Fix typo.
Rename IRQ handlers for more consistency.
Update for irq handler name refactor.
Update for latest IPin refactors.
Update for latest Delay refactors.
Add initial (mostly dummy) support for EFM32.
Refactor, implement delay_since() in terms of expired().
Make register access functions common.
Add bitfield accessors.
Allow to specify clock divider for freerun().
Andd %ld, %lx for printf().
Refactor to let switch to non-default LED easier.
Add Port 3.
Add signed and unsigned decimal prints.
Case long long calcs to uint32_t, fixes ambiguity with timer delay.
Add toggle method to Signals.
Double-include protection.
Add support for arbitrary sleep intervals (now accepts interval duration).