CMake fixes for hardcoded paths and more

Similar to my pull request for the other repository, the CMake issues are largely fixed. Remaining is the reliance on the other project being built in the directory "build" but I didn't want to add a whole install setup and find script for the other project. 

In the actual code I removed some references to the OpenNI grabber. To get this to work for me I had to make a failed build of PCL where it tried to use the OpenNI stuff but didn't find it so that it could find the needed header files.  It may be worth looking into copying those into this project or using another mechanism to find them.

The extracted point clouds appear to have some significant intrinsics issues. I'll make this my next priority.

edit: I also made this work with the head revision of PCL. You may or may not want to incorporate this.