GitLab

Combined the myriad ScannerExceptions and ParserExceptions to a single ParserException class that has a message and a line/column position in the file where the error occurred.

Fixed a silly bug in the simple key pushing (queues are FIFO!).

Instead of deriving different tokens from a base Token class, we now use an enumerated TOKEN_TYPE to distinguish types. This is so we don't have to cast all the time when parsing the resulting token stream.
Also, removed start/end stream tokens.

Will be completely wiped, I think, in favor of a Scanner (to tokens), then Parser mechanism.