Collect all errors from all passes, rename and document some of them

[Mingun]

Some fields in data model filled by the compilation passes which is not obvious at all. To make this clear, I document properties which is filled by passes, document that passes and rename one of them. In the end, now all passes implements PrepocessStep and handled uniformly. Error in one value instance no more prevents from reporting errors in other value instances or reporting warnings and type problems