Update of helpers

* Added GDAL helpers
* Updated Qt helpers
Update of advanced datastore descriptor

* Added method giving list of items IDs
Action for add of datastore items

* Added dialog for adding items in datastore
* Updated AppTools for QStringList conversions

(references OpenFLUID/openfluid#292)
Actions for moving datastore items up and down

* Added moving actions associated to up and down buttons
* Added automatic replacement of spaces in ID of datastore item 
  during adding process
* Updated french translations

(closes OpenFLUID/openfluid#292)