ENH: support resolution navigation into the file : clean and small refactoring about best level of detatil refactoring + reduce the file acess

BUG: Fixing #633 and #639 - Set the right focus policy for GlImageWidget, and remove keyboard grab in main application

ENH:  - connect the ql manipulator and the centralview manipulator to change regionon a ql mousePressEvent
      - connect the vectorimageModel and the CentralWidget on spacing change

     * implement needed methods to center viewport on the physical coordinate clicked in Ql

     - add a spacing parameter to the signal ModelImageRegionChanged in order to initialize proprely the spacing in the manips
     - forgotten update when using the mouse wheel
     - add a slot OnSpacingChanged to be able to update the spacing in the manips when a new resolutio is loaded

COMP: remove call of QString::fromStdString since it causes runtime issues on windows, when Qt and Mvd are not built with same VC version

ENH: support creation of Monteverdi2 windows NSIS installer. Preliminary import of MacOS bundle support file (untested)

ENH: implement the quicklook virtual_buildModel : write the ql to disk if multi-res or shrink the input image if not