Added Moveit adapter package

This implements the Descartes `RobotModel` interface for MoveIt.  The PR includes some parts of PR #13, but not all.  Method implementations for `TrajectoryPt` are not included.  However, these methods will simply be wrappers around RobotModel calls when required.
> I added this dependency only to find out that I didn't have `cmake_modules` installed. 

catkin itself contains a CMake config file (`eigen-config.cmake`) for Eigen in Hydro (see [here](https://github.com/ros/catkin/tree/groovy-devel/cmake/Modules), `groovy-devel` is also used for Hydro). This was changed in Indigo, where a `FindEigen.cmake` was added to `cmake_modules`, and `catkin` no longer provides the config file for Eigen.

So not depending on `cmake_modules` works in Groovy & Hydro, but will stop to work in Indigo. Adding the dependency on `cmake_modules` will not affect Hydro compatibility, but will make your package more future proof.

See the Indigo [migration](http://wiki.ros.org/indigo/Migration#cmake_modules) guide, and the `cmake_modules` [readme](https://github.com/ros/cmake_modules).

>  Everything worked before adding the dependency, so I'm not sure it is really needed. I think the dependency on `moveit_core` pulls in `Eigen`, though I'm not sure. 

I've seen Dirk Thomas tell people multiple times that they should not depend on transitive dependencies, because they can change and are not under your control.

I agree that the Eigen dependency is ubiquitous, and unlikely to change soon, but in principle I agree with Dirk. Be explicit about your dependencies.