fast_info usability improvements

[ValueRaider]

fast_info usability improvements:

• Add support camelCase dict keys, and officially support these, but secretly continue to also support snake_case keys
• Add dict functions values() and items()

[sanyearng]

I wasn't aware of the following dependency, but am posting here as FYI, as it surprised me:

I could not get Ticker.get_history_metadata() to function unless both a) Ticker.fast_info was first run; and additionally Ticker.fast_info.items() (for 0.2.9)

Delete or ignore this comment if this is otherwise obvious or intended.

[ValueRaider]

Did you should see this message?

RuntimeError: Metadata was never retrieved so far, call history() to retrieve it

It doesn't make sense to request metadata before fetching the real data (e.g. history). If you think something different should happen, request in a new Issue.

[sanyearng]

Did you should see this message?

RuntimeError: Metadata was never retrieved so far, call history() to retrieve it

It doesn't make sense to request metadata before fetching the real data (e.g. history). If you think something different should happen, request in a new Issue.

Perfect. My mistake.