Disable bluetooth when going to low power mode.
Merge branch 'fordboard' into 75-bluetooth-lowerpower
Disable Bluetooth when going to sleep.

Fixed #75.
Let PLL0 be disabled automatically - workaround not necessary.
Disable LEDs before going into lower power mode on LPC17xx.
Disable unused peripherals on the LPC17xx - no visible power savings.
Disable all LPC17xx peripherals before sleeping.

This may happen already but it's unclear from the manual. No current difference.