Synchronize reference and input pointcloud for ICPRegistration

Synchronize reference and input pointcloud for ICPRegistration if `~synchronize_reference` is set to True

Pink points are the output of LINEMOD and light green pointcloud is refined by ICP.

![linemod_icp_refinemen](https://cloud.githubusercontent.com/assets/40454/5525416/e557d0cc-8a28-11e4-81a7-7e61f4d65a0e.png)