Delete class elements that are not used (clean up code).

Add check whether external var matches to global var.

Also check FB passed as parameters in FB/Function calls (Thanks Andreas!)

Minor changes needed to build with pedantic flag.

Also check external/global variable consistency in configurations and FBs.

add method for printing class_name. USE ONLY FOR DEBUGING!

store POU reference to POU declaration instead of global var declarations.

Start declaration check class.

Start declaration check class.

Adjust coding style.

list_c: initial capacity. ERROR_MSG(msg,...) supports optional arguments now.

Deleting datatype checks no longer needed (with a view of making search_expression_type_c redundant).

Start adding support for data type checking of enums.

Remove comment no longer valid since introduction of constant folding.

Add some comments.

Update configure script.