Connect to a V-REP robot.

Sync pos (set only).
Todo:
- refactor dxl controller
- still connection issue?
- doc updates (controller and io abstractions)
Update import and installation
Update vrep io doc.
Correct a bug in from_vrep.
AbstractController, IO and StoppableThread
veep new controller/io API compatible
Avoid cyclic import in the config
use abstraction in dxm controller and io
Update the inline doc.
More cyclic import issues
Correct bug in dynamixel controller
Inline doc update
Add motor abstraction.
Merge branch 'refactor-controller' into vrep
Using stoppable thread in the primitives
Correct a bug in the primitive.
Add the alias in the v-rep robot.
Merge branch 'vrep' into refactor-controller
Loading scene, starting, pausing simulation