Default to building with GDI

Add setwinsize and setwinpos
Move blit from rect into gdi_thread
Add beep support
Add (non-functional) settitle support
Support ciolib scaling in addition to GDI scaling
Add window-size snapping
Support -iG in SyncTERM

GDI is still the second-least preferred mode, so auto mode will only
use it if the windows console somehow fails.  But at least people
can play with it.