Added 'track number' field to JSON API for track object
Don't HTML-escape names in api responses
Add "fromDate" param to api to allow retrieval of music items based on when they were added

This is needed for syncing so we can use a timestamp as a sync marker
API change: fromDate param now requires ISO 8601 format instead of POSIX time
Throw exception if fromData param cannot be parsed
Minor cosmetic tweak to parsing dateFrom param