MongoDB, background fetches, indicators of deleted messages, bug fixes.

Server

• MongoDB support contributed by @Googlom. Thanks!
• Support added for delayed presence notifications for background data fetches: it's possible to defer sending presence notification by some seconds when attaching to topic. Useful for automatic background data sync on mobile phones.
• Breaking change in configuration due to breaking changes introduced by Google in FCM: cc9d3f0
• Multiple bugs fixed, new and old.

Full list of changes: v0.16.2 - v0.16.3

iOS

• iOS Tinode is now available in the app store!
• Automatic background data fetches on receiving a push notification.
• Firebase Analytics added.
• Indicators of deleted messages.
• Multiple bug fixes.

Full list of changes: v0.16.2 - v0.16.3

Android

• Automatic background data fetches on receiving a push notification.
• Chinese translation contributed by @pcgpcgpcg. Thanks!
• Multiple bug fixes.
• Indicators of deleted messages.

Full list of changes: v0.16.2 - v0.16.3

Webapp

• BREAKING CHANGE in FCM config: tinode/webapp@6fee1ce
• Indicators of deleted messages.

Full list of changes: v0.16.2 - v0.16.3

JS SDK

• Support for indicators of deleted messages.
• Bug fixes

Full list of changes: v0.16.2 - v0.16.3