Removed outdated fixme.
Added infrastructure for built-in functions. Implemented print-function.
Tests included.
Added variables to the TRIPLA-language, including tests.
Added generated tokenizer and parser classes, with variables feature.
Now Tripla-interface throws an error on unsuccessful parsing.
Previously, an error was not thrown until compilation.
Added lazy variables to the parser. Test included.
Added lazy variables to abstract machine and compiler. High-level tests
included.