created rigid transformation class and voxel filter with accompanying test
Added unit test for Voxel Grid Filter
registered voxel filter average descriptors param as bool
Check for memory allocation error when using too small voxels
Merging in changes from master
Merge branch 'master' into unstable
fixed gtest include to point to local version
added small program to compare running time of 2 data filters
Added voxel grid filter to data filters tutorial
updated doc for included gtest
started writing PLY file parser
wrote load PLY files
added PLY save function
Datapoints can now load/save to ply files
Merge remote-tracking branch 'remotes/origin/unstable'