Swift plugin templates

Just opening a PR so we can track progress.

- [x] Make Swift template
- [x] Fix Swift compilation problems
- [x] Add the 6.1beta UUID so the plugin loads
- [x] Fix bundle loading errors
- [x] Add default scheme for running Xcode.app in debug mode

Here's the newest error caught from the system log
```
Sep 23 11:24:33 yamanji.local Xcode[39686]: WARNING: Failed to load plugin at path: "/Users/supermarin/Library/Application Support/Developer/Shared/Xcode/Plug-ins/SwiftPlugin.xcplugin", skipping. Error: Error Domain=NSCocoaErrorDomain Code=3587 "The bundle “SwiftPlugin” couldn’t be loaded because it is damaged or missing necessary resources." (dlopen_preflight(/Users/supermarin/Library/Application Support/Developer/Shared/Xcode/Plug-ins/SwiftPlugin.xcplugin/Contents/MacOS/SwiftPlugin): Library not loaded: @rpath/libswiftAppKit.dylib
	  Referenced from: /Users/supermarin/Library/Application Support/Developer/Shared/Xcode/Plug-ins/SwiftPlugin.xcplugin/Contents/MacOS/SwiftPlugin
	  Reason: image not found) UserInfo=0x7fecae45b000 {NSLocalizedFailureReason=The bundle is damaged or missing necessary resources., NSLocalizedRecoverySuggestion=Try reinstalling the bundle., NSFilePath=/Users/supermarin/Library/Application Support/Developer/Shared/Xcode/Plug-ins/SwiftPlugin.xcplugin/Contents/MacOS/SwiftPlugin, NSDebugDescription=dlopen_preflight(/Users/supermarin/Library/Application Support/Developer/Shared/Xcode/Plug-ins/SwiftPlugin.xcplugin/Contents/MacOS/SwiftPlugin): Library not loaded: @rpath/libswiftAppKit.dylib
	  Referenced from: /Users/supermarin/Library/Application Support/Developer/Shared/Xcode/Plug-ins/SwiftPlugin.xcplugin/Contents/MacOS/SwiftPlugin
	  Reason: image not found, NSBundlePath=/Users/supermarin/Library/Application Support/Developer/Shared/Xcode/Plug-ins/SwiftPlugin.xcplugin, NSLocalizedDescription=The bundle “SwiftPlugin” couldn’t be loaded because it is damaged or missing necessary resources.}
```