PCL_COMMON: removing default destructors - part 2

[lightyear15]

Empty default constructors: what a waste of typing!

• Follow-up of merge of pull request PCL_COMMON: removing default constructors/destructors #3440 -
  @SergioRAgostinho : here it is

[SergioRAgostinho]

I've highlighted below some comments which should also be ok to remove.

[SergioRAgostinho]

Note to maintainers: squash before merge.

[taketwo]

This PR introduces the following warning:

../keypoints/src/narf_keypoint.cpp: In member function ‘void pcl::NarfKeypoint::clearData()’:
../keypoints/src/narf_keypoint.cpp:75:52: warning: deleting object of polymorphic class type ‘pcl::RangeImage’ which has non-virtual destructor might cause undefined behavior [-Wdelete-non-virtual-dtor]
     delete range_image_scale_space_[scale_space_idx];