More not relevant/dead/commented out code

- `SpecialNames` - Note that the last change made to it was when the traits code was formatted using `black`. Before that, we get to the first commit which introduced this code into the github traits repository - at which point it was already commented out. Additionally, `SpecialNames` is imported in the `has_traits` module but it is not actually used anywhere from the looks of it - https://github.com/enthought/traits/blob/49ef397abbdd63c45806dfa074b30e7cc57a77a2/traits/traits.py#L1359-L1369
- Duplicate/commented out `Date` and `Time` trait definitions - originally introduced in the commit - https://github.com/enthought/traits/commit/012a951ea3ebf4c296694e2fe9803c66acf0731c but there are two sets of definitions in `trait_types` and in `traits` https://github.com/enthought/traits/blob/49ef397abbdd63c45806dfa074b30e7cc57a77a2/traits/traits.py#L1372-L1377
- `__newobj__` - used to unpickle new style objects but on Python 3 (and Python 2.7 ?) all objects are new style objects - https://github.com/enthought/traits/blob/d5bc4fa967fef0a004f109203aaac6f65741486f/traits/traits.py#L607-L615