Look into better sharing API

[dlew]

As described here: http://developer.android.com/training/secure-file-sharing/index.html

[dlew]

I've taken an in-depth look at this. While the FileProvider is in theory good, there are a few serious problems hampering my ability to use it:

1. FileProvider depends on granting URI permissions in the Intent. That's all well and good when the URI is the Intent's data, but it doesn't work when the URI is the Intent's EXTRA_STREAM. In those cases we still need to figure out a way to grant global URI permissions, which isn't any better than copying to the SD card.
2. There seems to be a bug with how Hangouts interacts with FileProvider. Since Hangouts is one of the primary use cases of Rage Faces I can't risk breaking interactions. More details here: http://productforums.google.com/forum/#!category-topic/hangouts/i-found-a-bug/messaging/android-mobile/aLdef6FxUXs

Once I can get around these two issues I'll look into this again.