Updating PROGMEM declarations and renaming Piccolo.pde to Piccolo.ino

Just some minor changes to fix the piccolo example code for newer versions of Arduino.  The PROGMEM declarations in Piccolo.ino and ffft.h were changed.  I've verified that this build works on an Uno board.  Code builds on Linux, Arduino 1.0.6 and avr-gcc 4.8.2.