Updated cloud io functionality - removed dependency from VTK legacy
More proper OpneCv+Qt+Vtk issues handling (http://code.opencv.org/issues/3492)
cloud collection merges data only on rendering
fixed size_t/int conversion warnings
proper render call order (fixes some issues with VTK6.1)
default meshlab background
Fixed all OpenGL issues for Macos (via objective-C++ layer)
cloud collection finalize
casting Vec3b operator for viz::Color
Added WidgetMerger, Polyline - colors support for each point independently, simple widgets now compute color array instead of setting global color
fixed crash for windows if console widow is closed or CTRL_C/CTRL_BRAK keys in console are pressed.
source compatibility with master
iteractor work
Fix for #3554

v4l2_scan_controls_enumerate_menu is unused and causes ioctl error on
RaspberryPi and possibly other Video4Linux variants. See
http://www.raspberrypi.org/forum/viewtopic.php?f=43&t=65026 for more
detail.
Remove clReleaseDevice call (workaround for pure  virtual call on Windows)
iteractor work
tuned some tests
Clarifying comments
Merge pull request #2443 from waveform80:issue-3554
Merge pull request #2445 from ilya-lavrenov:ocl_perf