Cherry pick v5.3.2 changes

[tobrun]

This PR cherry-picks all the 5.3.2 changes from master to the release branch:

TODO

• merge and cherry-pick Validate zoom level before creating mapbox telem event #10959
• create changelog and cherry-pick PR Update changelog for v5.3.2 #10982
• merge and cherry-pick handle null call instances in HttpRequest #10987

Changelog proposal

## 5.3.2 - January 22, 2018
 - Validate Surface creation before destroying [#10890](https://github.com/mapbox/mapbox-gl-native/pull/10890)
 - Add filesource activation ot OfflineRegion [#10904](https://github.com/mapbox/mapbox-gl-native/pull/10904)
 - Save configuration of UiSettings [#10908](https://github.com/mapbox/mapbox-gl-native/pull/10908)
 - Do not overwrite user-set focal point [#10910](https://github.com/mapbox/mapbox-gl-native/pull/10910)
 - Camera callbacks for velocity animated movements [#10925](https://github.com/mapbox/mapbox-gl-native/pull/10925)
 - Allow changing the used OkHttpClient [#10948](https://github.com/mapbox/mapbox-gl-native/pull/10948)
 - Validate zoom level before creating telemetry event [#10959](https://github.com/mapbox/mapbox-gl-native/pull/10959)

[LukasPaczos]

I think we should postpone upgrading to Java 8 until the new PR with followup changes to #10402