Added ExportCloudsDialog class for convenience when Viewing or Exporting clouds/meshes
Added Export grid map action
Clouds shown in the 3D Map view can be directly saved without cloud regeneration.
git-svn-id: http://rtabmap.googlecode.com/svn/trunk/rtabmap@1621 f169173b-cf89-36c8-b27e-44dbe73f0c83