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.
Modified OpenNI 1.x grabber to use generic pcl::io::* image types

* Should now use the same data types as the OpenNI 2.x grabber.
* Not tested with hardware yet.
Updated OpenNI 1.x grabber client programs to use updated image types

* pcl_openni_viewer
* pcl_openni_grabber_depth_example
* pcl_openni_grabber_example
* pcl_openni_image
* pcl_openni_save_image