Created framework for customizing properties dialog (changed access mods from private to protected )

[JLudwig2552]

Changed accessibility of default property editors so they can easily be overridden

Also created a few function that can be overridden to instantiate a subclass instance instead of the default (so the tabs can be customized by overriding the normal tab class)

[tracylynne99]

Downloaded PR to local branch on 09-feb-2020, awaiting more testing before final merge into master