Consider enabling comma separated parameter values about poshbot

[devblackops]

Just found this handy module that may help with determining the parsing logic using the AST.

https://github.com/lzybkr/ShowPSAst

[devblackops]

We definitely need this. When I wrote the CommandParser class I was aware that passing an array to a parameter was not going to work but I put it off for another day. Hopefully we can get this working soon.

[devblackops]

The parser has been rewritten in branch feat/command-parser-ast. I've done limited testing with it but so far it's looking good.

[devblackops]

Merged e722cc0 to enable this.