settings: Add margin between account buttons and option buttons.

This is a minor visual polish.

api: Remove console.log call.

We generally don't leave calls to console.log checked into the code;
they're noise in the source code, and typically also in the log when
looking there to debug something else.  This one is no exception.

compose: Make topic input uncontrolled.

Remove the `value={topic}` from topic text input, making it
an uncontrolled component.

To replicate the previous behavior:
 * initialize at the start in `componentDidMount`
 * make sure the topic input text is updated when we focus on
   the message input (it is invisible until then)
 * change the text on picking a topic autocomplete suggestion

Fixes zulip#2589.

prettier: Fix a bit of formatting.

I deleted a comment here and didn't expect that would change
Prettier's choice of formatting -- oops.

version: Bump version to 13.5.89, an Android-only stable release.

This release contains a workaround (zulip#2595) for an Android-only issue
in React Native upstream -- which itself triggers an iOS-only issue
also in React Native upstream.

So to thread this needle, we're releasing the workaround in an
Android-only release.

If we end up maintaining any kind of platform split like this for more
than a version or two, we'll of course want to do it with conditionals
in a single source tree rather than with different versions of our
codebase.

webview: Escape HTML in displayed errors.

In addition to the code in src/webview/html/, there's this one bit in
js.js where we build up some HTML.  Escape the data we interpolate
here too.

Because this code runs inside the webview and can't import from
our main codebase, and there's only a little of it, skip the fancy
template tag in favor of manually invoking an escape function.
On the other hand, take advantage of the browser environment to
implement that escape function very simply.

ui: Improve compose box buttons and spacing

* more consisntency in padding of compose input between platforms
* larger touch areas for all buttons
* move all related styles to composeBoxStyles
* buttons on left and right are precisely vertically aligned

webview: Queue unsent events until webview ready to process

* waits for 'ready' event and tracks status in `isReady`
* if it needs to send an event but not yet ready, queue in `unsentMessages`
* when ready send if any messages were queued

Add support to getNarrowFromNotificationData for group narrows

For this to work we need to parse a string of comma delimited
numbers of the recipients. This data is not yet passed to the
function; we keep the function flexible and functional by making
the parameter of `usersById` optional.`

webview: Pass baseUrl and authorization headers

* ensures that relative URLs are resolved correctly
* allows loading of any resource needing authorization