Enhancement of the Primitives examples

* Added variables produced by generators
* Updated simulation functions signatures
Add of an empty Datastore tab in Builder

(references #81)
Add of an AdvancedDatastoreDescriptor

(references #81)
Datastore tab now can display, remove or move items

(references #81)
Creation of the Datastore "add item" dialog box structure

(references #81)
"Add item" dialog box implementation for single files

(references #81)
"Add item" dialog box implementation for directories

(references #81)
Add associated files to the "Add item" dialog box

(references #81)
Improve design of the "Add item" dialog box

(references #81)
Reset fields at "Add item" box opening

(references #81)
Update associated files on file path manual change

(closes #81)
Fix Builder crash on unit creation
Fix Builder input data columns order

(closes #144)
Fix checking of generator produced vars
Switch to version 2.0.0~alpha3

* Enabled the build of GUI libs and OpenFLUID-builder in default
  CMake configuration
Add a check of produced input data

(references #96)
Add produced input data to displayed function information
Forbid non-unique datastore item ID

(closes #23)
Add of checking for version and ID of wares

* Added checking of ware version against current ABI version
* Added checking of ware ID in file name against ID in signature
* Added tests for wrong ID and wrong ABI version
* Renamed attribute for validity control of plugin container
* Cleaned ware plugin manager code

(closes #2, closes #70)
Fix of the  simulation function ID of CMake module test