Some files needed to be changed manually.

Contributed by luzpaz.

Differential Revision: https://developer.blender.org/D5801

Explicitly specifying DATA was redundant anyway, as that was the default.

Differential Revision: https://developer.blender.org/D5240

Note that some scripts still used the 3D view cursor which has been
removed for a while.

This should take care of most of the class property conversions to
use the new annotation format (colon instead of equals) for
assignment. There may still be a few edge cases that were missed.

Differential Revision: https://developer.blender.org/D3746

Bumped version to 2.4.2
Pep8 cleanup
Moved scene properties to a property group
access it through context.scene.auto_mirror
remove the properties upon unregister

Add poll checks for Mesh objects to operators
Add missing operator description

Remove the draw function from the AutoMirror operator
since it is not used and enabling Undo will not work
in this case, since depending on the initial settings
it can produce unwanted results