RandR: Fix issues discovered here during testing

RandR: Fix issues discovered here during testing

- Add some more debugging printouts
- When we initially plug in a monitor, set to Clone by default
- During initial clone, we cannot assume the plugged-in device
supports the same Mode so try to find a mode based on size.
- On output changes, test that an output has a crtc assigned.
- If a detached output Was the primary monitor, reset primary in config
to a valid existing monitor.
- Improve output_crtc_find code for better detection of where we can
place a new output.
- Fix "preferred mode" detection error.

Signed-off-by: Chris Michael <cp.michael@samsung.com>