Extended API to add tracks to a jukebox with custom IDs, to remove tracks, to query the number of registered tracks and the largest track ID seen.
Added basic unit tests
Bumped version number to 0.2
Regenerated documentation to incorporate new API, reformulations and spelling fixes
Updated README file (version history and installation instructions)
Add ordered_idpool.operator[] convenience method
Merge pull request #6 from dominikschnitzer/id-handling

API extension: add tracks with custom IDs, remove tracks, and more