The TTY module stores top/height but the Apple monitor stores
top/bottom. If top changes, bottom should remain unchanged.
Improve the POKE 34 shim, and add a test.
Fixes#32
The RdAltChar (mousetext) is not accurate. Under Virtual II it seems
to always return true if the 80 column firmware is active, regardless
of which character set is active.
* Fix ON GOTO and ON GOSUB - Should resolve#11
* Fix ON GOTO and ON GOSUB better - Should handle edge cases
* Fix ON GOTO and ON GOSUB - Added unit tests
* Fix ON GOTO and ON GOSUB - Fixed unit tests
