Fix: add missing line break and pcl namespace in error message
Fix issue #601

A segfault were raised when selection or triangle are not valid pointers.
Just test and skip them in that case.
Merge pull request #609 from nizar-sallem/fix_obj

Fix obj
Fix: bug when same detector is used for more than one input

When using same detector for more than one input (different clouds),
normals are not reset which causes false results or error if the clouds
sizes don't match.
Merge pull request #610 from nizar-sallem/fix_harris_3d

Fix: bug when same detector is used for more than one input
fixes #578, SHOTEstimationBase needs to be exported for app feature_matching
Merge pull request #611 from fran6co/fix-features

SHOTEstimationBase needs to be exported for app feature_matching, fixes #578