first released version of andor sdk3 plugin (andor neo + hydra ?)

This is a working version of the andor-sdk3 based pluggin. It has been tested (and works) in the context of the LimaDetector tango server (C++, SOLEIL). Though coverage is incomplete and python interface has nearly been tested.

Don't hesitate to review and request changes to be done (and pull-request re-submitted) before accepting it.