Sleeping for a minute, waking up, rtc running.

The low-power/rtc part seems to be under control.
Changing style
Initial commit of PWM module
SPI moved to B15
Merging EPD
Merging EPD source into project
PWM use to toggle pin at 175kHz

Used by epd charge pump
Added pwm and epd
Tested low-level functions of EPD

Pins toggling on demand, SPI write seems ok, epd_transaction seems ok.
Initial PWM commit
Initial timer commit

Moved systick timer here to provide timer functionality.
Initial usart commit

Provides serial comms, currently just by writing into a register.
Adding fifo support
Testing uart
Merged conflicts
Merged conflicts from stashing
More stashed conflicts merged
Trying to switch on the EPD

No success yet.
Addinf FIFO suppor
Initial commit of FIFO files

Will provide a FIFO for the usart