Add expression parser, fix some other issues
Add parser to other commands
Replace strtol with expression parser in the run command
Fix small typo
Add output to `run` command
Change one `tui` test to show incorrect behavior
Fix debugger issue
Add newline after help output of print_expression
Fix TUI not finding commands with arguments

This is due to the find_best_command command being too greedy, for some reason
Fix / Improve hexdump output
Improve TUI non-0 return message
Add preliminary stack command, change some error handling in parse_expression, and change parameters to optional in hexdump
Fix hexdump being called from other commands crashing z80e
Fix the `stack` command running the command even after showing help
Change hexdump help text
Merge branch 'master' into debugger
Merge pull request #11 from puckipedia/debugger

Debugger additions