Add IK Service result seed type, new validation

IK Service now uses a robust fallback procedure to try multiple
types of seeds to get solution, including ability for users to
supply their own joint seeds to try. This diff updates IK Service
example to use new result_type[] validation field, which combines
if solution is valid and the type of seed that eventually produced
the valid solution.

* Adds new method of validation to IK Service example using the
  result_type[] field.

* Also shows how to unpack byte array created by rospy to compare
  result_type[] properly with Msg seed/result constants.

* Reports result type and copy of response message data now.
Merge pull request #26 from RethinkRobotics/update_ik_seed_example

Add IK Service result seed type, new validation