Pymodaq

Cleaning up some bugs related to new functionalities

* :feature:`0` DAQ_Move_plugins: added the method *set_position_relative_with_scaling* to have correct steps in relative motion
when scaling options are set
* :feature:`0` all modules: debug info contains now name of package, method and script line where the error has been generated
* :feature:`0` h5_browser: a right click on tree items shows a context menu. so far possibility to export current item (data)
in ascii text file (%.6e precision format).
* :feature:`0` module scanner (daq_utils.scanner) has been created. Deals with lines or area selections within any viewer2D modules. Used for DAQ_Scan
and some others plugins (for area selection if needed). Most of the scan type settings (of daq_scan) have been moved to scanner
that is now a subobject of daq_scan

Huge modification related to the scanning. Now you can select an area in one of the opened 2DViewers. This viewer could for instance be a calibrated camera referring to the x and y positions of a XY stage. The Plot2D scan 2D viewer can also be used. Say that you just did a 2D scan and now you want to scan a cross-section within!! This area can be a 2D one (rectangle, 2D scan type) or a PolyLines (linked segments, 1D scan type). Random modes and others are still available in this mode

DAQ_Scan updated with averaging possibility. Opens up a new dock showing the current scan average. All scan in the average are saved

plugins removed from repo. pymodaq_plugins repository created as a standalone project