Making interfaces to handle stm value types more flexible so that it's easier to mix in maps and lists with the same interface.
Added more flexibility to dirty map elements to support eventual non-value types, like lists.
Added a basic container class (parent class of struct, list, map).  Current version only supports holding value types.  Will update soon.
Added a test case to exercise some of value map logic.
Added a value list type.
Tests for value list operations.