Fix error when using shortest configuration

TypeError: Cannot call method 'match' of undefined
Fix missing argument validation on last option
Make sure we don't have an undefined token
Pass the list of unparsed tokens to the filter

This allows for more elaborate filters.
Merge pull request #13 from sabberworm/support-omitted-shortarg

Fix error when using shortest configuration
Merge pull request #14 from sabberworm/throw-error-on-last-rule

Fix missing argument validation on last option
Merge pull request #15 from sabberworm/allow-complex-filters

Pass the list of unparsed tokens to the filter
Added parser.parse to example

Closes #12
Reset arg if it was a switch and not an argument