First version of auto-DJ crates.
I need some feedback on the GUI, but otherwise this feature should be ready for merging into the trunk!
import chromaprint feature from libray_features branch
removed option to submit keys
added copyright information
Just some minor changes to comments.
Merged with trunk; minor updates to merge conflicting changes.
code clean up
adpot code to coding guidelines
removed bulky stuff that was not needed anymore
added API-KEY for mixxx
added KEY URL
merge with trunk
Now the auto-DJ-crates table stores the last time the track was played, and uses that to prioritize randomly-added tracks!
I thought the system didn't have that info...turns out it's stored as PlaylistTracks.pl_datetime_added for set-log playlists!

Also updated to latest trunk version.
Fix vamp-plugins SConscript to add the INTERNAL_VAMP_PATH to the include path correctly.
Merged with lp:mixxx
Made the auto-DJ-crates feature subject to conditional compilation.
Implemented an "Add crate" menu on the "Crates" tree-item in the "Auto DJ" feature.
One more convenient way to add a crate to the auto-DJ queue!
merge with trunk
removed valueChangedFromEngine()
unified word choice for pSender, pSetter is the a function pointer to set() for me