Fixed capitalization for Linux support

Hi,

I noticed that the latest update of the unstable branch had yielded some path/variable names inconsistencies regarding capitalization of OpenNI, which I suspect was unintentional (see for instance https://github.com/OpenNI/OpenNI/tree/unstable/Wrappers/OpenNI.java/src/org with 105 .java files in folder "OpenNI" and just one in newly-created folder "openni").

If I remember correctly, Windows is be case-tolerant, however these fixes are necessary for a proper Linux compilation. In summary, I edited all occurrences of string "openni" into "OpenNI" (as was done in the previous update) for files:
Wrappers/OpenNI.jni/org_OpenNI_NativeMethods.cpp (358 occurrences)
Wrappers/OpenNI.jni/org_OpenNI_NativeMethods.h (786 occurrences)
Wrappers/OpenNI.jni/methods.inl (459 occurrences)
Wrappers/OpenNI.jni/OpenNI.jni.cpp (2 occurrences)
Platform/Linux/Build/Samples/SimpleRead.java/Makefile (4 occurrences)
Platform/Linux/Build/Samples/SimpleViewer.java/Makefile (4 occurrences)
Platform/Linux/Build/Samples/UserTracker.java/Makefile (4 occurrences)
Platform/Linux/Build/Wrappers/OpenNI.java/Makefile (2 occurrences)
and merged folder Wrappers/OpenNI.java/src/org/openni/ into Wrappers/OpenNI.java/src/org/OpenNI/

Regards,

THP