* Update GLDisplay to version 1.4
* First implementation of multi-frame read through 3D ImageStack Data arrays
* Added CtControl::ImageStatusThread, controlling the ImageStatusCallback
  calls on image counter change events, with default rate limit
  (not blocking hardware acquisition) and improved coherence
* Added Thread::waitOn method to safely sleep on a Cond during cancelation,
  which uses pthread_cleanup_push/pop to release its mutex.
* Fixed bug not calling ImageStatusCallback with int. and w/o ext. soft ops
* Improved debug info. if image size mismatch between control and hw layers
* Improve ImageStatus counters monitoring in test_frelon_control.py
* Merged Tiago Coutinho image_events patch:
  * Added change events on std. image cntr. attrs. using ImageStatusCallback
  * Added last_image DevEncoded DATA_ARRAY attribute, pushing change events
  * Added gc command to trigger garbage collection
* Added last_image_pushes_events attr, controlling DATA_ARRAY change events
* Fixed Andor3 problem with non-implemented GetBitDepth in simulator camera
Merge branch 'multi_frame_read'

Conflicts:
	applications/tango