Added copyright notices to top of files.

Added copyright notices to top of files.
Updated documentation to be accurate.
Updated parser and producer classes to work with the modified API defined by SQL::Translate.
SQL::Translator instances have data members named parser_type and producer_type that can be used to determine from whence the parser and producer subroutines come.
SQL::Translator will accept parsers and producers in the form Class::Name::function, just like mod_perl, in addition to Class::Name (with the implicit function name), Name (relative to SQL::Translator::{Parser,Producer}, and anonymous subroutines.