Add "copy_all_fields" option to transformPointCloud***() functions

So far different transform functions had inconsistend behavior. Some
copied the data in all fields, some did not. Following the discussion
in #575, this commit adds an option to control the copy behavior.
Add a helper class EventFrequency

A helper class to measure frequency of a certain event. To use this
class create an instance and call event() function every time the event
in question occurs. The estimated frequency can be retrieved with
getFrequency() function.
USC: fixed parameters / added descriptor-type

Fixed the descriptor parameters matching the values of the original
paper (Tombari et al. 2010). The former values have been copied from
3DSC-descriptor and have not been adapted.

Added a descriptor type UniqueShapeContext1960.

Modified test case to match the new UniqueShapeDescriptor.
Fixed setCameraPosition in PCLVisualizer.

After setting the new camera position the camera clipping planes
where not adjusted which resulted in a black render window.
The site which pointed me in the right direction was
http://www.vmateevitsi.com/2011/10/25/vtkcamera-problem-with-setposition/
Fixed issue #874 by ensuring that h_index is never negative (which only appears to happen when distance is exactly 0).
Fix bugs in cone visualization
Added function to set playback speed for OpenNI2 grabber.
This only has an effect on file devices.
Fix bad orientation & origin propreties
Merge pull request #879 from VictorLamoine/ply_fix

[PLYReader] Fix bad orientation & origin propreties
Merge pull request #872 from nylocx/cameraPoseFix

Fixed setCameraPosition in PCLVisualizer.
Merge pull request #881 from taketwo/pr877

Fixes for Cone Visualisation
Merge pull request #882 from nylocx/oni2PlaybackControl

Added function to set playback speed for OpenNI2 grabber.
Fix shapes not drawing with VTK6
Minor tutorial fixes
fixing bug of estimating translation vector
Merge pull request #884 from VictorLamoine/local_doc_tutorial_fixes

Minor tutorial fixes
Merge pull request #883 from VictorLamoine/vtk6_fixes

Fix shapes not being drawn with VTK6
Merge pull request #875 from mohawkjohn/issue_874

Fixed issue #874 by ensuring that h_index is never negative
Merge pull request #885 from tttamaki/master

fixing bug of estimating translation vector
Added sequence number and timestamp to clouds.
The squence number and timestamp provided by OpenNI2 are now added
to the point cloud header field of the clouds returned by the callbacks.