Removed the ability to create the first user (admin) through the web interface
Reduced memory usage on random requests

Closes #2
Copy/pasting without enough checking causes errors
Switch to mutagen -> allow serving of more audio formats
Fix
Transcoding
Changed mimetype guessing

First look in system-known extensions/types through `mimetypes` module,
then in supysonic configuration
Stream: force content-type, in case Flask couldn't guess it
Updated README
Fix for audio formats without bitrate
Transcoding supbprocess error handling
Won't handle content-length estimation

This is actually a bad idea. If the estimated value is too low, clients
might close the connection before receiving the whole file.
Fix for files without tag

Closes #6
Added an 'exit' command to the CLI
Added configurable extension whitelist on the scanner

Closes #8
Added getting lyrics from text files

This needs work on the XML converter
New way of building XML

Less error-prone
Allows setting both attirbutes and text-data on a single element
Introducing client prefs

Allow setting default transcoding values for specific clients
Web UI update with client prefs. Saving don't do anything for now
Handle client prefs changes