Prepare for React 16.

* feat(filmstrip): show thumbnails with toolbar and on hover

* squash: reduce verbosity of logic for when to display

* squash: remove check for fake participant

Before fake participant (youtube video) would make the filmstrip
always displayed. However, youtube videos already dock the
toolbar, so filmstrip will remain displayed, so the check is
redundant.

* squash: change mouse hover listener targets

* ref(1-on-1): move remote visibility to a selector

Derive whether or not remote videos should display using a selector
to look across different states. A selector was chosen over using
memoized selectors (reselect) or subscribers as a first step
approach, avoiding additional mutations caused by a subscriber
updating the filmstrip state and avoiding additional api overhead
introduced by reselect.

* rename selector

This would better mimic React behavior where each component has
its own markup, instead of relying on markup existing elsewhere.

- Remove non-redux paths for hiding and showing remote videos.
- Hook web filmstrip to redux to know when to hide remote videos.
  This works, even though VideoLayout is handling RemoteVideo
  appending, because react is only monitoring filmstrip's declared
  JSX which does not change except for attributes (css classes).

* feat(indicators): move the "top toolbar" indicators to react

* wrap baseindicator

* fix(filmstrip-only): vertically align center the toolbar

Use top 50% to position the toolbar's top at the vertical center
of the iframe. Then use transform 50% to move the toolbar itself
up 50% so its middle matches the middle of the iframe.

* squash: toolbox should center with filmstrip

* feat(avatar): SmallVideo uses the existing Avatar component.

* feat(display-name): convert to React

- Create a new React Component for displaying and updating display
  names on small videos
- The updating of the Component is defined in the parent class
  SmallVideo, which children will get access to through prototype
  copying
- Create a new actionType and middleware so name changes that occur
  in DisplayName can be propogated to outside redux
- Update the local video's DisplayName when a conference is joined
  or else the component may keep an undefined user id

* squash: query for the container, not the el owned by react

- Create a new ConnectionIndicator component for displaying an
  icon for connection quality and for triggering a popover. The
  popover handling has been left in ConnectionIndicator for now,
  which follows the existing implementation.
- Remove the unused method "connectionIndicatorShowMore"
- Change the implementation of existing methods that update the
  connection indicator to call the same method which will rerender
  the indicator completely.

We've had Filmstrip & LargeVideo React Components on mobile/React Native
from the start. We didn't have them on Web (because the rewrite in React
is not complete yet). However, that led to differences in the React
Component Conference on Web and mobile. In an effort to get closer to
merging the React Component Conference on Web and mobile, introduce the
React Components Filmstrip & LargeVideo on Web even if a minimal
render-only form at this time.

The video status labels, which include recording and hd status,
have been moved back to the top left while in vertical filmstrip
mode. The following had to be done:
- Remove styling to move the labels to the bottom left
- For VideoStatusLabel, move filmstrip remote video count, toggle
  state, and 1:1 state into redux.
- Use middleware to emit out to the Recording label when the
  filmstrip changes.
- Create an empty Filmstrip file for web and identify the existing
  Filmstrip component as native.

left blank in default meet installations, to be overridden by adding <base href="CDN_URL"> to /base.html