install nodelet xml

Otherwise libuvc_camera produces a (non-fatal) error
on each startup and the nodelet can't be found.

install camera_node into the packages bin path

Conflicts:
	libuvc_camera/src/camera_driver.cpp

This is a module specific node and no general binary like ivcon,
convex_decomposition, catkin_make, etc.

Also it looks like it can't be called from launch files when installed globally

add an explicit dependency on generated files in CMake

This will make sure that the generated headers are build before they are compiled.