Merge drogon's 2014-07-14 & 2014-07-17 patchs

2014-07-14
Updated mostly to the gpio readall command to support the Raspberry Pi
B+

2014-07-17
Fixed a bug in the gpio readall command on model B's (caused by a
side-effect
of changing it for the B+)

Aded a gpio command: usbp hi/low - to change the usb power