Lib-jitsi-meet uses Temasys on Internet Explorer and Safari so it does
not make sense to require its adapter.screenshare.js on React Native,
for example, where it fails anyway.

Our JSHint configuration is not extensive and we have excluded multiple
files from linting. Additionally, we have seen JSHint to be unable to
parse newer ECMAScript features such as the object spread operator
(proposal).

On the other hand, we have seen ESLint to beautifully work on React and
React Native source code in addition to ES2015 and later. Introduce
ESLint alongside JSHint as an intermediate step to eventually switching
from JSHint to ESLint.

As our source code does not fully follow even the JSHint rules we have,
it is very difficult to introduce ESLint with many rules. At the
beginning, introduce it with as little rules as possible. Morever,
ESLint is able to automatically fix certain rule offenders so once we
have ESLint merged we can incrementally add new rules while keeping our
commits' modification on as little subjects as possible.

Add "onmute" and "onmute" handlers to the WebRTC MediaStream and trigger
corresponding RTCEvents.

Stores render event in connection times to use it for tests.

Moves render time calculations in the library.