added StringObject/StringValue
added ObjectDb.string()
name cleanup in StreamTester, FakeFileSystemTest
removed StringSet.contains()
added FakeString
added missing test to FakeFileTest
refactored StringSet to extends Iterable<StringValue> instead of Iterable<String>
added StringSetObject
added missing test to ObjectDbTest
fixed style in ObjectDbTest
reordered methods in ObjectDb
added StringSetBuilder
switched from using jdk String to StringValue for native function parameters/results
refactored FakeString
fixed naming in FakeStringTest