Removed ancient deprecated MemberVisitor class
Finally, Macaroni can deal with enums
Finally allow "struct" in addition to "class"

Basically a struct is a class in Macaroni with the "IsStruct" property
set to true.

In the process, I had to majorly change the Parser Lua glue which is
used in the tests to pass in a Target instead of a Library, which is
the deprecated way of parsing stuff.
Added docs for enums

Almost added an ability to generate a method for enums based on
annotations, but am going to hold off on that for today.