fixed power24 PCB date

The date on the PCB silkscreen for the power24 PCB
was wrong.  Fixed.
updated control_driver PCB date

Updated the date on the control_driver PCB to match
the power24 PCB.
PCB makefile now depends on Gerber files

Now, when the Gerber files are updated, the Makefile
will know to repackage the .zip.
doc power led, new power supply

Documented addition of power supply indicator led
and removal of transformer.

Removed obsolete power supply PCB (pcb/power).