Fix memory leak in AudioPlaySdRaw
Remove old version of AudioSynthWaveform. Fix sine wave generation to clean up its specturm and also fix ramping.
declare tone_incr to be volatile to prevent the compiler optimizing frequency() out of existence
Fix bug in PlaySynthMusic example - remove unnecessary include
Fix up synth_tonesweep and the example to conform (more closely) to the naming conventions
Merge pull request #24 from el-supremo/master

Remove old version of AudioSynthWaveform. Fix sine wave generation to cl...