Fix compiler warnings (reorder, unused) in Openni2
Merge pull request #668 from jspricke/fix_compiler_warnings

Fix compiler warnings (reorder, unused) in Openni2
Revert merge pull request #528

This reverts commit 70a9b93c6c0cb6d2666422905340a1708e694319, reversing
changes made to ec9d63dae69778f2cbeba86d7c33d4b872dcce2f.
Merge pull request #656 from taketwo/revert-528

Revert merge pull request #528
Add missing include directive for boost/chrono.hpp.
Merge pull request #671 from j-oberlaender/master

Add missing include directive for boost/chrono.hpp.
Avoid using namespace std in header files.
openni_pcd_recorder: Add command-line support for device IDs (like in openni_viewer).
openni_pcd_recorder: Improve calculation of default buffer size.
Merge pull request #674 from yangyanli/avoid_using_namespace_std_in_header

Avoid using namespace std in header files.
Merge pull request #673 from j-oberlaender/pcd_recorder_improvements

Pcd recorder improvements
Document the fields in pcl::PCLHeader.

Especially the interpretation of the timestamp field is important.
Merge pull request #684 from j-oberlaender/doc_improvements

Document the fields in pcl::PCLHeader.
Removed get[..]Stream() calls and added triggerSingleFrame(..)
Added single-frame triggering.
Merged shutdown(..) with ~OpenNI2Device(..)
Fixed abstraction around existing OpenNI 1.x grabber.

This should help with switching between OpenNI 1.x and 2.x grabbers.
Added fall-through to OpenNI 2 grabber.

If OpenNI 2 is being used, have openni_grabber.h include openni2_grabber.h.
Enabled kinfu CMake option with OpenNI 2.
Disabled some kinfu classes that depend on OpenNI 1.x when OpenNI 2 is being used.