missing image viewer AST properties in the preference dialog

[kswang1029]

This is a user request from the Helpdesk.

Currently in the WCS and Image Overlay tab of the preference dialog, we can set up properties like the following

The user wanted to be able to configure title, numbers and labels as well. The goal is to be able to configure a set of defaults for everything rendered in the image viewer widget (title, grid, color, colorbar, etc).

There are two ways to do this:

1. We add missing properties (there will be quite some!) in the preference dialog
2. We make the settings in the image viewer widget persistent, aka, "sticky" as implicit preferences.

[loveluthien]

Adding a button to save the current setting in the image view?