Create MoveIt Tutorial for TracIK

[Dave Coleman]

Currently the tutorial for using TracIK with MoveIt! exists in a README in this repo, but would you guys be interested in moving it to the unified tutorial website? We already have a stub page created for it, we just need someone to create the PR: http://docs.ros.org/indigo/api/moveit_tutorials/html/doc/trac_ik_tutorial.html

I think this would increase visibility of this IK option for MoveIt!

[Dave Coleman]

I've created the tutorial:

https://github.com/ros-planning/moveit_tutorials/pull/41

Perhaps this can be the master version, and the version in a README in this repo can point users to the moveit tutorials?