Xcode Megazord project

[garvankeeley]

Prototype of what this might look like, the base branch is swift-rc-log.

• String+Free.swift exists twice, this needed renaming
• Errors.swift same as above

[garvankeeley]

The xcode project itself contains all the files from Logins and FxAClient, nothing too fancy happening here:

[thomcc]

I'm a little surprised you need the separate libsqlcipher.a, but this looks really good!

[garvankeeley]

I don't know if libsqlcipher.a is needed, I was trying to preserve the bits from the Logins and FxAClient when I mashed them together. This isn't compiling, I am getting a ton of Rust symbol errors, as if no symbols from the megazord lib are being resolved.

[thomcc]

That's not good, I'll look into it after meetings. I wonder if the things we're doing to work around rust-lang/rust#50007 don't work on iOS (when I checked before they seemed to, but hard to say)

[garvankeeley]

the "umbrella header" for cross lang linking isn't correctly specified, fixing it now

[garvankeeley]

All that is left is a minor issue with the queue being defined in both projects.
I'll look at containment of that var now.

[garvankeeley]

In order to split up this WIP commit to the parts that are immediately landable, I did this PR
#625