New types. Sized ints and aliases.

- Defined the :[u]int{8,16,32,64} types by looking at the sizes of
  the built-in types.
- Removed :[u]int{8,16,32,64} from cffi-clisp.
- New typedefs: :uchar, :ushort, :uint, :ulong, :llong, and :ullong.
- New test: misc-types.sized-ints.
- Removed the related TODO items.