Servo calibration

This is now worky for testing, what is the goal :

- One place for servo settings and calibration process ( mapping etc ... )
- Share settings automatically ( or not ) between differents script

- Refactor inmoov configs ( not yet but that was necessary for later steps, more : http://myrobotlab.org/content/new-style-config-mrl-custom-robots-and-inm... )

UI is optional, you can set values from script, like before. But now values are stored inside related json file inside .myrobotlab folder .

Can be loaded with a simple servo.attach() -> controller ( if here ) and other things are parsed from servo.json.