(gui) Add a custom command to perform update on all diagrams
(XdfResource) Now use the default EMF fragments generator

Useful when diagram is serialized with links to network objects
(updater) Improve error management
(gui) In layout feature, correctly detect network ports
(gui) Add doc on "Update all diagrams" command
(gui) Remove useless specific cases for invalid connections
(gui) Remove useless INVALIDATED_REFINEMENT constant

Invalid refinement is detected when refinement URI is unresolvable
(orcc-lib) Move thread-related code to orcc-native library.
Update CHANGELOG.md
Merge branch 'net_serialization_updates'
Update current version to 2.1.0
Update CHANGELOG.md
Update CHANGELOG.md
(gui) Correctly update df connection in restoreConnections()
(gui) Refactoring: rename methods related to instance refinement
(gui) New specific method to update refinement and restore connections
(gui) Refactoring

Delete saveConnections() and restoreConnections() methods.
Their content have been moved to updateRefinementAndRestoreConnections() method
(gui) Fix issue introduced in 04b51e1ed

Copy/paste is evil :rage:
(updater) Fix NPE when a project's file have no suffix