BREAKING: bot: Enumerable removed @deprecated...

...and things that should have been deprecated, specifically `some`
bot, bot_io, hop: support Iterable as arg (instead of List)

more general, more better
BREAKING: Going with Sequence over ListBase

Avoid exposing 'not supported' members if not necessary
bot: file rename: list_base -> sequence.dart
bot: ReadOnlyCollection creates a fixed-length list for copy ctor