one problem is that there is now case for the beginning of type checking (empty context)

undo method for changer so we iterate over the same change and now can configure which node to apply the change to

Generate is_X for constructor X without arguments, is needed such that transformation is correct if error step is skipped

extended synthesizer as well

# Conflicts:
#	inca-translation/solutions/TypeLangTest/TypeLangTest.msd

# Conflicts:
#	inca-translation/languages/TypeLang/generator/template/TypeLang.generator.util.mps