Fixed a setter issue that affects some unit tests too

Fixed #379

Fixed an issue due to the introduction of lazy loading a superclass f…

…rom a class.

Added a way to lazy loading extern superclass at runtime

Minor typo fixed

Improved error handling and detection

Improved error handling

An error must be reported even if in the same line a warning was already reported.
Unit test added.

Added preliminary support for Struct. Fixed a bind method. Unit test …

…added.

Fixed an issue with super keyword. Unit test added.

Renamed optional classes and fixed a setter unwanted side effect.