marsyas/basis.h: fix for c++11
marsyas: compile in c++11 mode
core: implement lockfree realvec-based queue
marsystems: improve AudioSink, AudioSource wrt reliability, latency

* Use lockfree queue to pass data between RtAudio thread and MarSystem
  thread.

* Do not busy-wait for fixed amount of time when queue full/empty.
  Instead, wait on a condition variable.

* Never wait in RtAudio thread if queue full/empty. Instead, return
  right away, writing silence in case of AudioSink. Only block
  MarSystem thread.

* Implement new "realtime" boolean control, which will minimize buffer to
  force smallest logically possible latency at the cost of tolerance to
  processing times of other parts of system.
cmake: add macro to enable c++11 for given target
cmake: marsyas: use 'target_enable_cpp11' macro
Ported GStreamerSource to use GStreamer 1.0
Removed the #ifdefs which became unnecessary when GstreamerSource was moved into the 'optional' directory.
marsystems: AudioSource/Sink: suppress useless warnings
marsystems: AudioSource/Sink: state source of error on RtAudio error
Added liblinear, a package for training and predicting with Linear Support Vector Machines to otherlibs.  Added SVMLinearClassifier.[h|cpp] but did not hook these up to liblinear yet.
Added nextract, a program that extracts features and outputs to a text file
Changed nextract to be simpler and to write out files in libsvm/liblinear input format
Small cleanups to nextract
Added ability to output the current time of the slice instead of the label, useful for predicting unknown data with libsvm/liblinear
Put texturestats in nextract.  This obviously helped the classification with liblinear a lot.
tempo: add doubling heuristic and SVM

Still something wonky with the BP calculation.  I thought it
wasn't so significant but it distorts the svm values quite a bit,
so I'll go back and take another look at it.
core: MarSystem: add getter for controls map
marsyasqt: Marx2DGraph: add method to change data + dimensionality
introduce qt5apps: inspector