Add of an empty Output browser tab

(references #79)
Add of a basic FileChooser for Output browser

(references #79)
Add the path and a reset button to output browser

(references #79)
Removal of plugin file checking when adding an Observer
Merge branch 'remove-addObserver-check' of https://github.com/alibres/openfluid into alibres-remove-addObserver-check
Fixed AdvancedDomainDescriptor::addUnit
* added dfs on graph method
* added check arborescence method
Management of graph arborescence

* Added Edge cleaning flag visited
Reactivation of MapView

* Replaced calls to SimulationBlob and CoreRepository with AdvancedDomainDescriptor

(closes #100)
Cleaning of source code

* Moved observer and function registry classes from ware namespace 
  to machine namespace
* Cleaned unwanted character in #include directive
Replace Output browser with a custom one

* Added ability to choose the application to use for opening a file

(references #79)
Add a Delete option in output browser

* Desactivate popup menu for directories
* Added ability to delete the selected file

(references #79)
Refactoring of tests

* Refactored Primitives tests
* Moved functions signature registry tests into the right place 
  (machine unit tests)
* Updated other tests (including builder unit tests) according to 
  the primitives tests refactoring
* Removed deprecated tests and datasets
Add monitoring in output browser

* Added a monitoring of displayed directory, allowing widget update if changes occurs

(references #79)
Improve of output browser

* Added information on navigation bar
* Added alternate rows color
* Added sorting capability
* Added ability to delete with the "suppr" key, one or many files at once

(closes #79)
Merge branch 'improve-output-browser' of https://github.com/alibres/openfluid into alibres-improve-output-browser
Fix a test dependency
Creation of the demo home button

(references #80)
Creation of an empty "Open demo" dialog box

(references #80)
Make project preview widget as a reusable component