Refactoring: Separated Parser from Grammar

Pash.Implementation.Parser is now the class used for parsing.
It has a name conflict with Irony.Parsing.Parser, but this shouldn't
matter as only Pash.ParserIntrinsics classes should be using the Irony
namespace at all. All other classes should use the new Parser class.

I also removed the second ParseException class. All parse exceptions
are now System.Automation.Management.ParseExcpetions.
Parser class Support for partial parsing
Implementation for partial cli input. Doesnt compile
Fixed 'InternalsVisibleTo' attribute
Support for showing the last control statement keyword on partial parse
Throw ParseException if parser crashes for easier error handling
Appending newline to read input; test
Merge pull request #323 from sburnicki/partial_parsing

Support for partial parsing