Adopt new XML-schema according to IEC61131-10

Our current CFC/XML implementation is based on the tc6-version of the 61131-3 standard, which is largely incompatible with the newer 61131-10 version. We should look into refactoring our implementation to adhere to the newer standard and offer a conversion to allow users to port their existing projects. This would ideally be done in the IDE, independent of the compiler.
