Multiply/Divide the PC and SP registers by 2 for gdb

Signed-off-by: Josh Kilmer <srjek2@gmail.com>
Some Makefile fixes and comments

Signed-off-by: Josh Kilmer <srjek2@gmail.com>
Merge branch 'master' of ssh://acm/~/git/dcpu16
addresses are word-based, lengths are byte based, as far as gdb is concerned

Signed-off-by: Josh Kilmer <srjek2@gmail.com>