(refs #6924) Support for record field access syntax.

Because the record field access syntax is harder to implement when the
old Variable access syntax is also supported, this feature is only
enabled (and Variable disabled), when the following module header is
used:

module {
    fields
}

This change contains also refactoring and cleaning up of code
related to variable resolving and field handling.

Change-Id: I8e877573131d501e1a6e63bdde39e064df9ded39