Allow spatial connections modifications during simulation stages
Fixed simulation variables usage in KML observer 

* Added ability to take latest available value if no value is available
on current time step
Add of Firespread example project and simulators

(references OpenFLUID/openfluid#20)
Update of Firespread example project and simulators

* Added definitive dataset
* Fixed computation of fire production

(references OpenFLUID/openfluid#20)
Merge branch 'develop' into develop-qt
Add a method to remove a PolygonEntity from a PolygonGraph

* Refactored removeEntity() method for LandRGraph and LineStringGraph
* Added a removeEntity() method  for PolygonGraph
* Added related tests
 Add a method to clean Edges of a PolygonEntity
    
	* Added A cleanEdges() for PolygonGraph
    * Refactored removeEntity() method  for PolygonGraph
    * Added related tests
Add a method to get PolygonEntities by Min Area
    
        * Added a getPolygonEntitiesByMinArea() method for PolygonGraph
        * Added related tests
 Add a method to merge two PolygonEntities
    
  * Added a mergePolygonEntities() method for PolygonGraph
  * Added related tests
Merge branch 'develop' into develop-qt
Add of enabled flag for pluggable wares

* Added enabled flag for simulators, generators and observers
* Cleaned code
Update of Firespread example simulators

* Updated spatial graph information in signature

(references OpenFLUID/openfluid#20)
Model and monitoring management in OpenFLUID-Builder

* Added basic coupled model management
* Added basic monitoring management
* Added display of signatures

(references OpenFLUID/openfluid#246)
Add of parameters management for wares in OpenFLUID-Builder

(references OpenFLUID/openfluid#246)
Reorganization of source code files in OpenFLUID-Builder

* Moved common files from base subdirectory to common subdirectory

(references OpenFLUID/openfluid#246)
Introduction of a graphical view of models in OpenFLUID-Builder

(references OpenFLUID/openfluid#246)
Add of variables IO in graphical view of models in OpenFLUID-Builder

* Added simulators and generators grahics, with IO slots
* Added connectors representing variables

(references OpenFLUID/openfluid#246)
Add of variables names in model view in OpenFLUID-Builder

* Added variables names as connectors labels
* Cleaned code
* Added model view options

(references OpenFLUID/openfluid#246)
Export of model view to files in OpenFLUID-Builder

* Added export to image (PNG format)
* Added export to vector (SVG format)

(references OpenFLUID/openfluid#246)
Add of items in model and monitoring management in OpenFLUID-Builder

* Added simulator selection dialog
* Added generator creation dialog
* Added observer selection dialog
* Updated placement of items in model view
* Added icons for wares status
* Cleaned code

(references OpenFLUID/openfluid#246)