Xcode 13 Support

[astromonkee]

There's currently an issue with building the project using Xcode 13 due to one of the changes introduced in Swift 5.5.
The issue occurs on the X1Kit submodule.
I've sent a PR to fix it and hopefully we can just update the submodule reference if it's merged.

[redlinejoes]

I ran into a build issue with X1Kit and Swift on Xcode 13 as well. I was also able to resolve it too.

[don17sch]

@astromonkee it may be better to fork X1kit. it has not had an update in several years.

[cgutman]

Fixed in c930a46 by switching to my fork of X1Kit with @astromonkee's patches.