Fix vamp-plugins SConscript to add the INTERNAL_VAMP_PATH to the include path correctly.
Push launchpad to github migration scripts.  WARNING very site-specific -- not usable without hand-editing
Fix return type in TwoWayMessagePipe.
Check for NULL before TrackPointer deref.
Make per-branch build directories and sconsign-files. This saves build results and signatures for different branches in different folders. This drastically reduces the need to rebuild the world when switching between branches in git.
Merging from lp:mixxx/1.11.
Backport Owen's git support changes to the build system. lp:mixxx r3379,3381-3384.
Cherry-pick lp:mixxx r3398 to get the last of Owen's git migration changes.
Merging from lp:mixxx/1.11