Added ability to select preferred verb instead of the first one.

Hi Adrian,

I thought it would be a good feature to be able to use several overloaded verbs and have parser to select preferred one based on the following parameters:
 - verb name,
 - parameters count,
 - and parameter names

I think this can be handy when somebody (like me) needs to execute same verb with different parameters like as follows:
 - myexe install /db /u:user /p:password
 - myexe install /website
 - myexe install /service
 - myexe install /etc

I have added code and tests.

Best Regards,
Mikalai Kardash