first changes for atari5200 target
add get_tv()
add some conio functions
use __RESERVED_MEMORY__ to reserve memory for the default 20x24 text screen
add gotox, gotoy, and gotoxy
Merge remote-tracking branch 'upstream/master' into a5200
Merge remote-tracking branch 'upstream/master' into a5200
atari5200 update: simple conio "hello world" works now
Added the long-missing driver-flags byte to the potentiometer (mouse) drivers.
Migrated the phantom-key exorcism code to the other C128 mouse drivers.
Back-migrated some phantom-key rejection optimizations.
Added comments that explain why some instructions are implied.
Merge pull request #114 from greg-king5/phantom

Added the phantom-key exorcism code to the other C128 mouse drivers.
Added a fast subroutine to multiply two signed 8-bit numbers.
Fixed the comments to say where the actual Left-Hand Side and Right-Hand Side are put.

A description of positions [left, right] is appropriate more for C code than for Assembly code.  (A description of timing [first argument, second argument] is more appropriate for the way that Assembly code is written.)
add dummy irq.s
add joystick driver -- trigger buttons are not queried yet
clrscr for Atari 5200 default conio screen
Fixed a ca65 internal error that would show a message when a name is exported both outside and inside a scope.

Jeremy Turner described the bug, on the original cc65 mailing list.  It was fixed by Ullrich von Bassewitz.
Merge pull request #115 from greg-king5/cc65-mul

Add a signed 8-bit times 8-bit multiply function.