fix for #1363 - use clearMap instead of reset to clear costmaps (#1412)

* -fix for #1363. -created clearMap function for each layer. -use clearMap instead of reset to clear the costmaps

* -function name change -infilation layer clearMap change -make resetMap a pure virtual function

* Changing clearMaps back to reset

* Fix uncrustify error

* Fixing lifecycle transitions and tests now that reset doesn't act as a cleanup function

* Updating this based on the approach taken in PR #1431

* Moving voxel_grid reset to the resetMaps function.

* Missed adding resetMaps back to header.

* Adding some comments to help navigate the inheritance hierarchy