Issue #2298687 by tstoeckler, Jose Reyero, hussainweb, rpayanm: Sequence and Mapping implement interfaces incorrectly, make them honest about what they support

Revert "Issue #2298687 by tstoeckler, Jose Reyero, hussainweb, rpayanm: Sequence and Mapping implement interfaces incorrectly, make them honest about what they support"

This reverts commit 43370336.

Issue #2298687 by tstoeckler, Jose Reyero, hussainweb, rpayanm: Sequence and Mapping implement interfaces incorrectly, make them honest about what they support

Issue #2264179 by Gábor Hojtsy, vijaycs85, alexpott, benjy: Clarify use of property/undefined and add an ignore type in configuration schema.