inconsistent naming of header file in Simple Waveform Genetator with Arduino Due example

[tritch]

inconsistent naming of header file in example: "Simple Waveform Genetator with Arduino Due"

"FunctionGenerator.ino" codes references "Waveforms.h", yet this file is referred to as "Waveform.h" in the example: See lines 383 and 312 on html source for "Simple Waveform Genetator with Arduino Due"

[shfitz]

Fixed to make the names consistent.