Add support for more file formats

[Lucas-Mc]

It has come to my attention that there are several file formats which are commonly used in the community, but are not supported by this package. I would like to keep these all open-source; here are my thoughts so far:

• FLAC
• Ogg (with embedded Vorbis and FLAC)
• GDF (if not already a subset of the current EDF implementation)