Moved ngon creating function from obj_import into BPyMesh so other importers can use it.

Exporter free's mesh vertex data each run (was causing memory errors when exporting fluidsim meshes... poke ken for Mesh.Unlink() since many meshes are still created)
Exporter had an indentation error also.
Added an NMesh wrapper around Mesh for importers to use, so as to work around slow 1 by 1 adding of data. used in upcoming flt_importer update.
Mesh cleanup now has the dangerous option to perform a cleanup on ALL mesh data. (needed it for a project)

release/scripts/obj_export.py

@@ -167,12 +167,12 @@ def copy_images(dest_dir):
 		# Get MTex images
 		if matname != None:
 			mat= Material.Get(matname)
-				for mtex in mat.getTextures():
-					if mtex and mtex.tex.type == Blender.Texture.Types.IMAGE:
-						try:
-							uniqueImages[mtex.tex.image.name] = None
-						except:
-							pass
+			for mtex in mat.getTextures():
+				if mtex and mtex.tex.type == Blender.Texture.Types.IMAGE:
+					try:
+						uniqueImages[mtex.tex.image.name] = None
+					except:
+						pass
 	
 	# Now copy images
 	copyCount = 0
@@ -463,6 +463,7 @@ EXPORT_GROUP_BY_OB=False,  EXPORT_GROUP_BY_MAT=False):
 		
 		# Make the indicies global rather then per mesh
 		totverts += len(m.verts)
+		m.verts= None
 	file.close()