Adding automated UI tests for Umpleonline

[RalphNgassa]

No description provided.

[RalphNgassa]

These tests are categorized as follows according the aspects of umpleonline they verify

• dynamicResizing: Inspects the layout of the web app
• exampleLoading: Ensures that examples (class diagrams, states machines...) are properly loaded to the web page. Both the source code and the model
• diagramEditing: Ensures that models can be modified seamlessly. These modifications include but are not limited to adding/removing an association, a class or a generalization.
• positionDiagramEditing: Verifies the position of model elements
• optionsMenu: Inspects the functioning of every button present in the options menu

Both the Ant and Gradle build scripts provide instructions on how to launch these on your local machine. Finally, new test cases could be added in the near future.

This pr fixes #363.