RingRTC (along with WebRTC) are no longer included as submodules; now
they are a nearly-standard pod dependency with an extra "prebuild
checksum" to download the built artifacts.
This removes the submodules as well as the storing of the WebRTC
artifact repo commit in the app's Info.plist. RingRTC already prints
the current version in debug logs, so we're not losing anything.
I followed the instructions from `BUILDING.md` and turned off the Push Notifications. I successfully compiled the application from the latest source code and installed it on my iPhone. I was not able to setup a test account using the installed app. According to [this post](https://whispersystems.discoursehosting.net/t/trouble-using-signal-for-ios-installed-through-xcode-on-one-phone-with-signal-installed-through-app-store-on-another-phone/705/17) when the Push Notifications are turned off some steps from the setup account procedure are not executed and account creation fails. I turned the Push Notifications back on and was able to finish setting up the account. I believe the proposed note will be useful for future contributors.
Per discussion [here](https://community.signalusers.org/t/not-able-to-build-in-xcode-9-3-9-4/3498/12).
Using `--recurse-submodules` will init and update all submodules, so you can do everything at once. I find this a bit nicer.
(Also, it seems like it might be more reliable with GitHub forks?)
I realize `make dependencies` runs `git submodule update --init`. It will just be a no-op if you clone this way.
copy/save/delete is accessed via longpress for all media messages, just
like for simple text messages.
Notes
-----
We don't support saving audio attachments as it's not clear where they should go.
(I don't think users expect them to end up in their iTunes library.)
There is still no UX for "pasting" media into Signal.
Removed the now redundant (and confusing) "share" button interface.
//FREEBIE
