Fix #42, #48: Allow for arg > 0, add arg sorting, and warning message…

[landure]

… when format is invalid.
Fix #42 and #48.

• Modify how @arg is handled to allow for $10 and up values, in the hope to add support for short and long options in the future.
• Auto-sort arg by number in output, ending with $@.
• Add a colored warning on stderr when @arg line format is invalid (bonus).
• Add a test case for numeric @arg.
• Ignore @noargs lines with text.

Hope this changes fits your expectations.