Use a single websocket connection per browser, removing the need for an
extra websocket connection per target.
This is thanks to the Target.sendMessageToTarget command to send
messages to each target, and the Target.receivedMessageFromTarget event
to receive messages back.
The browser handles activity via a single worker goroutine, and the same
technique is used for each target. This means that commands and events
are dealt with in order, and we can do away with some complexity like
mutexes and extra go statements.
- Refactored API calls to be cleaner
- Changed types that shoudn't be exported to not-exported
- Updated examples with API changes
- Added unit test for Title action
Changed implementation of ElementVisible/ElementNotVisible to use a
javascript evaluation instead of the previous, cumbersome
implementation. As this may not work correctly in all scenarios, the old
versions will remain as ElementVisibleOld and ElementNotVisibleOld until
the new implementations can be vetted for correctness/performance.
