0.5.1 (#37)

* 0.50.1
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switch to flat mode connection.
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Parts are rewritten to use flat connections in the protocol.
Why?
    - iframes are included in most operations.
    - tab got a new method: `await tab.get_frames()`
    which will return Iframes that are inspectable.
    - find() will include iframes, so you can even search for "verify you are human" and
    click the verification checkbox in js challenges.

Since this required quite some rewriting, please test thoroughly, especially if you run large projects.