Added SetEqualityConstraints.


git-svn-id: http://scalatest.googlecode.com/svn/trunk@5162 fd1274fd-080f-5963-8033-43ee40fcd1de
Added MapEqualityConstraints.


git-svn-id: http://scalatest.googlecode.com/svn/trunk@5163 fd1274fd-080f-5963-8033-43ee40fcd1de