NSoperation

* Back to NSOperation. Seems like it crashes a little less often :)
* Back to separate UIWebView per each View Controller (in storyboard), i.e. no more shared web views

It seems to crash only occasionally, when using other apps in between, especially Safari, etc. I'm using iPhonen 4S and iPad mini retina, and on both devices it's lightning fast, esp. on that A7-powered retina mini.

All crashes seem to be related to findenv/getenv calls. We should further analyze TestFlight crash logs.