Add mouse window controls and finer display scaling (#63)

Add configurable mouse and wheel bindings, window move and resize, tab drops, cross-output dragging, and device settings. Adjust display scaling in 0.05 increments.

Preserve opposite-edge positioning during scrolling resizes and show rows for edge drops into tabbed columns.

scripts/tests/test_presentation_isolated.py

@@ -117,6 +117,7 @@ class Presentation(unittest.TestCase):
                 self.assertEqual(count("idle"), idle)
                 target.stdin.write(b"u")
                 target.stdin.flush()
+                windows(0)
                 time.sleep(.6)
                 self.assertGreater(count("idle"), idle, "unmapped inhibitor must stop inhibiting")
                 target.stdin.close()