Fix bugs (natario1#630)

* Use CopyOnWrite set in GL preview (Fix natario1#626)

* Demo app - do not add frame processor when opening (Fix natario1#628)

* Add comments

* Create EngineThread annotation

* Fix onVideoResult crash for snapshots

* Catch IllegalStateExceptions in applyRepeatingRequestBuilder

* Add exception to LOG.e

* Add changelog

* Release v2.3.1

* Move snapshot logs to verbose

Release v2.3.0 (natario1#608)

Release v2.2.0 (natario1#573)

Release v2.1.0 (natario1#541)

Release v2.0.0 (natario1#531)

Release v2.0.0-rc2 (natario1#519)

Release v2.0.0-rc1 (natario1#508)

* Bump version

* Clarify changelog

* Remove README header

* Add whitespace

Release version 2.0.0-beta06 (natario1#495)

* Bump version

* Fix javadocs

Quick fixes & bump version (natario1#471)

* Fix natario1#460

* Fix natario1#419

* Fix natario1#443

* Bump version

* Fix natario1#425

* Fix test

Bump version to 2.0.0-beta04 (natario1#402)