Fix T42000: STL export scale incorrect.

Not a bug, in fact, more like a feature request.
Added an option to take into account scene's scale on both export and import time.

Also added scaling/axis conversion to importer.

io_mesh_stl/blender_utils.py

@@ -21,11 +21,14 @@
 import bpy
 
 
-def create_and_link_mesh(name, faces, points):
+def create_and_link_mesh(name, faces, points, global_matrix):
     """
     Create a blender mesh and object called name from a list of
     *points* and *faces* and link it in the current scene.
     """
+    from mathutils import Vector
+
+    points = tuple(global_matrix * Vector(p) for p in points)
 
     mesh = bpy.data.meshes.new(name)
     mesh.from_pydata(points, [], faces)