#2 Clean up command-line flags

[Wolfgang Faust]

• Remove -v flag (and associated code), since it did absolutely nothing.
• Document -o and -d flags

Code: branch 'clean-ops' of https://github.com/wolfgang42/tibasic-code.git

[Wolfgang Faust]

Also on that branch: a somewhat improved options parser which complains about unknown flags, and always uses the last argument as the input filename.

[pcmattman]

Merged. Thanks!