Adapt tlc594x driver for using multiple channels.
Fix misuse of ALWAYS_INLINE in atmega::SpiMaster.
Rewrite UI led drivers using virtual functions and adapt examples.
Merge branch 'develop' into feature/multiple_output_tlc594x
Add isRunning() method to LED classes.
Fix double indicator stopping in first flash.
Merge branch 'feature/multiple_output_tlc594x' into develop