Query string parameters
Track documentation
Refactored Track resource

If an artist or album are given as parameter, the file's metadata is ignored.
Testing track with non-existent IDs
Added utils tests
Merge pull request #136 from tooxie/utils

Added utils tests
Merge pull request #135 from tooxie/tracks

Tracks
User model
User metadata
User resource
Documentation on Users
User tests
Turned db_model into a class attribute
Token-based authentication
Added shiva-admin utility

This utility script will be used for some administration tasks like user
creation.
[WIP] Admin documentation