- added tests for all functions defined in l2o.d.ts in Disposable,
Enumerator, Dictionary, Lookup
- removed workaround definitions for spec#3.5.2 (it produced more
problems)
- fixed Lookup.toEnumerable
Via TS spec #3.5.2 generative recursive are disallowed (restriction will
be removed in the future), so added workaround.
Disposable interface extracted from Enumerator