Many new features and options

**Forgot variable for end of data for songs with metadata...

- Added option to enable handling of metadata (ID3,INFO) tags and
skipping over them for playback
- Added retrieval of Song, Artist and Album info from ID3v2.3 and
INFO/LIST tags
- Added different PWM ramping methods for Uno vs Mega types to prevent
popping sounds
- Enabled direct usage of SDFAT library (better performance and resource
usage)
- Added option to enable Stereo WAV files and output (4 Output pins with
multi-mode)
- Added option to enable Support for 16-bit files and pseudo 16-bit
output (4 pins as 2 in multi mode)
- Added option to use TIMER2 for compatibility when using Uno type
boards
- Added option to begin playback at a set number of seconds into the
track
- Modified timer aliases and arrays for better board support
- Added debug option to enable some error output to serial
- Moved user config options to pcmCOnfig.h file
- Added function to generate standard format WAV file with header
- Added function to finalize digitally created WAV file once data is
written
- Probably a few things I forgot to mention