Sound for Wii U and other minor fixes

[jtothebell]

• Refactor song and note structs to not use bitfields, but manually read/write the correct bits from the data byte arrays. This fixes audio on the Wii U (and potential future Big Endian platforms)
• Increase audio volume by removing bit shifting that was intended to reduce clipping, but doesn't appear to be helping
• Turn off logger by default (stop unnecessary disc I/O)
• Only write cartdata file on cart closure to avoid pauses mid game