m430ia2p: update urdfs based on DH data. For #54 and #63.
m430ia2f: update urdfs based on DH data. For #54 and #63.
support: add 'base' link (transform to World Coordinates). Fix #101.

This should not affect existing kinematic plugins or MoveIt configurations:

 - the link is not part of the main kinematic chain
 - the transform is implemented as a fixed joint
m430ia2f: fix mirrored meshes. Fix #109.
Update readme.