Added kinematics plugin that uses Levenberg-Marquardt method

Here I propose to include a new kinematics plugin: `lma_kinematics_plugin`

This could be a good alternative to the default Newton-Raphson plugin (aka. `kdl_kinematics_plugin`) because is faster and more effective.

I've performed a test with 100.000 valid goals (poses) for [this](http://www.azorobotics.com/images/equipments/EquipmentImage_251.jpg) 6 DoF robot and these are the results:

| Plugin                              | Solved (%)  | Mean Time (ms.)  |
| ------------------------------- |:---------------:|:----------------------:|
| `ikfast61`                         | 99,6            |   1,8                      |
| `kdl_kinematics_plugin`  | 81.3            |   9,2                      |
| `lma_kinematics_plugin` | 96,2            |   1,6                      |

All of them check that the solution is within the joint limits defined in the URDF.

Will perform tests against other robots.