Make update installation bulletproof

[nikDemyankov]

Need to make update installation more bulletproof. That should involve better communication between installer and loader. Plus, a way to rollback to the previous version, if something terrible happened during the update installation. It already has a rollback mechanisms, but it can be improved.

[andreialecu]

I'm seeing the following for some(?) users on iOS:

Base version on app store has JS version 1.0.0. The JS version currently available on the update server is 1.0.18.

One of my friends on iOS 8.3 can update for a while to new versions, then randomly fails one of the updates, and CHCP reverts back to 1.0.0 and then no further updates ever work without him reinstalling the app from the app store. Unfortunately, I don't have much more info

This is probably the same as the Android issue I have sent a PR for, and may be fixed by one of the recent updates to CHCP, like: 4f0c334

My binary still uses the plugin version from before Nov 22.

[nikDemyankov]

Thanks for the input. That task is in top priority through all other github issues. Hope to fix that and some other stuff before the New Year. Just need to finish some company work first.

[nikDemyankov]

Actually, I have some ideas how to make it more stable with better rollback. And this should also fix CSS caching issue on the iOS. Just need time to work on that. So please, be patient :)

[andreialecu]

No worries. Just an update that I have now gotten a similar report from a iPhone 6 plus running ios 9.1 which also had to reinstall from app store to be able to get back up to the latest version.

[nikDemyankov]

Made some improvements to the update download/install mechanism. Closing this issue, since v.1.2.0 of the plugin is out.