Merge SourceKitD.swift and DynamicallyLoadedSourceKitD.swift

With the merge of `SourceKitD` and `DynamicallyLoadedSourceKitD`, there is no longer a need to have two files.

Author: ahoppen

Sources/SourceKitD/CMakeLists.txt

@@ -6,7 +6,6 @@ set(sources
   SKDResponseArray.swift
   SKDResponseDictionary.swift
   SourceKitD.swift
-  DynamicallyLoadedSourceKitD.swift
   SourceKitDRegistry.swift
   sourcekitd_functions.swift
   sourcekitd_uids.swift)