Move code in Xhgui_Db to Xhgui_Profiles.

If we want to have user editable watch functions, some classes need
to be renamed as the current names won't make sense anymore.

Add Xhgui_Profiles to be a collection wrapper for the profile data.
Rename test case property.
Update consumers of Xhgui_Db to use new class.
Merge pull request #9 from preinheimer/refactor-db-code

Refactor db code