Improve OSM large maps performance on exporting to OpenDS

[breznak]

• jMonkey crashes on too large (Blender?) files, investigate optimization paramaters
• we should be able to export a reasonably large section of a map, eg Prague city

[breznak]

@JohnnyMarek I want this fixed, we don't have to do it ourselves but we should find proper developers to cooperate with. CAn you identify the following?

• [ ] The resulting simulation is slow/crashes because the file is too large, because some complex objects (Buildings?) have too many edges?
• [ ] the fault why the objects are too complex is in OSM/Blender/jME3?
• [ ] please share links to solutions you have found/tried
• [ ] where is the upstream (issue tracker, ML) that we can contact about this?

[breznak]

@mykkro this may be a shared issue, so let's keep track & cooperate