Fixes some issues around Xcode 9 yelling about using UIKit on background threads

[rhaining]

In Xcode 9, the new main thread checker kept warning me about FastImageCache using UIApplication's isProtectedDataAvailable on a background thread. This should be innocuous, but I think Xcode 9 is just broadly looking at UIKit on background threads.

More consequently, this was preventing me from running unit tests locally on my own project.

The basic change here is to use NSNotificationCenter to watch for notifications when protected data becomes available or unavailable, and maintain that state as a static variable, which the instances can then utilize.

[rhaining]

This also resolves this issue: #150

[RodBrown1988]

@rhaining After chatting with @mallorypaine on Twitter, he has left Path, and this repo no longer has anyone with write access actively working on it.

I'm looking at upgrading my personal version of it, and perhaps starting a canonical side fork now that Path seem to have abandoned this repo.

[rhaining]

@RodBrown1988 dang! thanks for the heads-up.

[yoon-boom]

I guess can't find podspec, no maintenance (looks like they left path) only option is either fork-> create own branch then create your own podspec or manually hardcopy files is the only option.

[mallorypaine]

Please open PRs against my fork here: https://github.com/mallorypaine/FastImageCache

I will continue to maintain FIC even though Path itself is no longer maintaining it.

[Sega-Zero]

@rhaining, will you do this? I can make a PR if you don't have free time for it

[rhaining]

@Sega-Zero this PR is ready to be merged

[Sega-Zero]

@rhaining please, read the thread, @mallorypaine cannot merge it in this repo, we need a PR into a fork

[Sega-Zero]

@mallorypaine is it possible to transfer this repo to you? Is there anyone in Path who can do it?

[mallorypaine]

No idea. I don’t think there’s a single person left from when I was there.

[k-krzyszczak]

@rhaining ETA of new version with this merge?

[Sega-Zero]

@Jeaday this has been merged in mallorypaine#1

@mallorypaine Is it possible to update the pod? Or maybe create a new one?

[rhaining]

@Jeaday i don't work for Path or know anyone there. as far as i know, this project is unmaintained now. i have a fork over here https://github.com/rhaining/FastImageCache/ with those changes.