Shadow DOM support

[ingvar-nikiforov]

First of all congratulations on the release. I am super excited to start using this software.

Bug report:

1. Selector generation fails to match the element in shadow DOM. It matches the closest parent that is not in shadow DOM.
2. playwright.selector($0) for an element in shadow DOM returns error:

__playwright_evaluation_script__763:192 Uncaught TypeError: Cannot read property 'length' of undefined
    at Object.parseSelector (__playwright_evaluation_script__763:192)
    at InjectedScript.parseSelector (__playwright_evaluation_script__763:688)
    at Object.buildSelector (eval at extend ((index):733), <anonymous>:1032:43)
    at ConsoleAPI.buildSelector (eval at extend ((index):733), <anonymous>:351:36)
    at Object.selector (eval at extend ((index):733), <anonymous>:319:41)
    at <anonymous>:1:12
parseSelector @ __playwright_evaluation_script__763:192
parseSelector @ __playwright_evaluation_script__763:688
buildSelector @ VM1432:1032
buildSelector @ VM1432:351
selector @ VM1432:319
(anonymous) @ VM2126:1

Here is the site I was using to find these issues: fanteam.com