testplatform: Add testplatform implementation.
power: Add project config.
Readme: Add instructions for power project.
power: Init and deinit SC in the loop.
power: Remove EXTINT callbacks.
power: Init before toggling a led.
power: Simplify the structure (and fix issues).
Merge branch 'wip-power'

Merging non-working power branch to fix the compilation problem in
master.