Removed opt. flags from CMakeLists.txt and added PCL_DEFINITIONS
Removed opt. flags from CMakeLists.txt and added PCL_DEFINITIONS

These two changes are needed to compile RGB-D RTK with the same
configuration that was used to build PCL. Random seg. faults
and crashes occur if RGB-D RTK is used with flags different
than those on PCL/Eigen.

natalnet-lpr/rgbd_rtk,natalnet-lpr/rgbd_rtk,natalnet-lpr/rgbd_rtk