[#531] Feature font chooser

[jkcoding7]

This PR features a new Font Dialog for users to change the font and size to their preferred setting. This involved:

• Rename refactoring: FontSizeDialog -> FontDialog. This included additional renamings in EditorFrame and JetUML.properties.
• An update to UserPreferences to incorporate String preferences for the font name.
• Some additions and simplifications to the FontMetrics, CanvasFont, and StringRenderer API to improve text bound calculations.
• Renaming ITALICS -> ITALIC, and adding extra margins to give a more centered look for text in class nodes in TypeNodeRenderer.
• Modifying the existing tip of the day to highlight the new font chooser feature.
• Unit Tests: The EnabledOnOs annotation was opted for instead of the OSDependent method to run dimension calculation tests. Now, these tests run only on Windows operating systems. Also, with the addition of users being able to select fonts, the font name needed to be set and restored for a consistent testing environment.

[jkcoding7]

This is not ready for a pull, there are some tests related to dimension measurement that need to be updated.

[jkcoding7]

Unit tests have been added and updated, now ready for pull.