This follows a suggestion by Sijmen Schouten in issue #818.
Platoterm64 now works with mouse at 1200 baud.
Bump MOUSE_API_VERSION in asminc/mouse-kernel.inc.
Fix typo in testcode/lib/mouse-test.c.
mouse-test.c can be use to test all available mouse drivers for a given target.
Currently supported targets are Atari, C64, and C128.
To avoid confusion, rename samples/mousetest.c to mousedemo.c.