* If TW_THEME is not defined, then check both DEVICE_RESOLUTION and
TARGET_SCREEN_WIDTH x TARGET_SCREEN_HEIGHT for width/height. Use
the determined width and height to automatically select landscape,
portrait, or watch, as well as associated mdpi/hdpi.
* Improve the display of the error message so it fits in a standard 80
character width terminal without line wraps.
* Write relevant errors for missing themes that clarify what went
wrong.
Change-Id: I94b02349ce38bf6a9cecde403d78ff2490821d8a