Fix frame dimensions at initialization or when switching simulation mode

Closes #10 (closed)

This MR make sure the frame dim is property setup at start from the Tango property.

• The detector info was not up-to-date with the requested frame size
• Changing the simulation mode is not anymore resetting the frame size

This already fixes the issue.

But i have also reorder the tango simulator initialization to set the mode first, then the frame size. This could be removed from the PR.

With this MR i don't need anymore #10 (closed), cause we can do it by configuration.