Added license information to hardware READMEs

I finally found the Ice Tube Clock license information on the Adafruit
Ice Tube Clock pages, and have included that in the appropriate
READMEs.
Corrected C6 value in board schematic

In both the Ice Tube Clock kit and the xmas-icetube revisions, C6 is
22uF but was marked as 33uF in the schematic.  This has been fixed.
Updated hardware design manifest

The parts manifest has been reformatted slightly, and I now specify
voltage regulators from ON Semiconductors.  Their LM317 in particular
seems to be a more robust part according to the datasheet.