BG-486 / issue #37: Adding an informative exception when trying to post abstract classes.
Merge branch 'development' of https://github.com/okb/Pomona into development
Altering PostAbstract test to reflect canges in error handling
Adding an extra test that posts an abstract class, which fails on the server
Merge pull request #49 from doffen/development

Support for isAbstract property, and two tests testing that it's handled correctly
Removed obsolete class.
Optimize Maybe.Switch overload taking Func as argument when maybe does not have value.
Support exposure of ISet<> from resource.
Bumped version to 0.7.12 :)