Appinspector

What's Changed
* make appium depencency as optional
* compat with uiautomator2
* make print_json faster

**Full Changelog**: https://github.com/codeskyblue/appinspector/compare/v0.2.0...v0.2.1

What's Changed
* add cli, fix android dump_hierarchy, add appium sample code by codeskyblue in https://github.com/codeskyblue/appinspector/pull/4

New Contributors
* codeskyblue made their first contribution in https://github.com/codeskyblue/appinspector/pull/4

**Full Changelog**: https://github.com/codeskyblue/appinspector/compare/v0.1.2...v0.2.0

**Full Changelog**: https://github.com/codeskyblue/appinspector/compare/v0.1.1...v0.1.2