Recover from unproper resources deallocation

[jeanchristopheruel]

As mentioned in #47:

Since you mention the need to unplug/replug the camera, my first guess would be, that some process is still holding the camera connection open. Perhaps earlier runs from your python script did not exit cleanly and the camera handle has not been closed properly. If that is the case, the camera may refuse your attempt to talk to it, because it thinks there is still another process it should be associated with.

Vimba doesn't allow the user to recover from python exiting before proper deallocation of the Vimba resources. As a user, I would like to easily be able to recover from such a situation.