Tweak MPU temperature code
Change run script to default to release mode, like the Makefile
libpixi: introduce struct ProgramInfo

Used to describe version info and build info of libpixi and client programs.
Add build-version string, generated from 'git describe'
pio: eliminate use of libpixi *GetPinStates()
libpixi: remove *GetPinStates() functions
libpixi: rename *GpioPhys* functions to *GpioChip*
pio: add adc-monitor command
Initial DAC support: add dac-write command