Cleaned version of k-okada's simplfied meshes:

RSL: extra removed meshes.bak folder.

Squashed commit of the following:

commit d780643
Author: Kei Okada <k-okada@jsk.t.u-tokyo.ac.jp>
Date:   Thu Apr 10 13:24:49 2014 +0900

    add stl files for simplifer meshes, as suggested at RethinkRobotics#30 (comment)

commit 11aeffa
Merge: 557a2bc 1fa1833
Author: rethink-kmaroney <kmaroney@rethinkrobotics.com>
Date:   Thu Nov 21 13:21:08 2013 -0500

    Merge remote-tracking branch 'origin/release-0.7.0'

Author: rethink-rlinsalata