Allow setting RGB image size for OpenNI driver + Fix kinectClientExample

Hi,
this little pull request slightly extends two features of the kinect-wrapper.
1. It allows specifying carrier and remote in the kinectClientExample. So far, these options were existing but not used. Also, the documentation was misleading as changing "local" was documented to change the port name, but "name" is the actual option.
2. For the OpenNI driver, it was not possible so far to change the RGB image size. Therefore, RGB images were always at 320x240 resolution. The little fix introduces the capability to change image width and height.

Both fixes were tested and should work just fine.
@pattacini It would be great if you could merge this :).

Thanks and have a nice week,
Tobias