Initial commit of Firmware

  Initial firmware based on the code from solderlab.de
    with various changes , including pins used, number of
    columns strobed, and generation of random patterns
    when there is no input data
Eliminate LED flicker when cycling through colours

  Closes #1 - whereby LEDs have a noticeable flicker when cycling
   through the random colours.

   - Move the call to random() so that it is called at most once
      per loop, and that the time take to calculate new values is
      spread out, reducing the time paused when creating a new
      set of pixel colours