Updated docs, especially detailed internal API docs.

Updated docs, especially detailed internal API docs.
Updated default sub to return the data structure (and not the SQL::Translator instance). This became an issue once the subs were redefined to accept two args.
Removed the possibility to pass a filehandle (or something that can getlines) as an option to translate.
Added many levels of code folding markers.
Updated parser to use a named class::function style of defining a function to call, just like producer.