Uiautomator2

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* fix and add doc for app\_start 425, add uiautomator check in dump\_hierarchy
* add thread lock in dump\_hierarchy
* fix session restart
* Update README.md
* add notification about dingtalk travis

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* add wait gone
* add strict argument to session()
* rename UIAutomatorServer to Device, add session.restart() method
* change http://tool.appetizer.io to https protocol
* add swipe\_ext('right', 0.9) method
* add app\_wait, app\_list\_running

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* add swipe and screenshot to d.xpath element
* fix init with serial
* update changelog, remove d.watchers.watched, use IPython.embed first in cmd:uiautomator2 console
* add console in command line
* fix shell(stream=True) timeout error, close 394

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* fix android Q support again

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* replace google-fire with argparse, add current, stop, start subcommand in command line
* remove useless u2cli

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* fix init unknown host service, close 373
* add develop.md