Move the _Unicode module into _StringProcessing

.gitignore

@@ -1,3 +1,5 @@
+.DS_Store
+
 # Xcode
 #
 # gitignore contributors: remember to update Global/Xcode.gitignore, Objective-C.gitignore & Swift.gitignore

Package.swift

@@ -16,9 +16,6 @@ let package = Package(
         .library(
             name: "_MatchingEngine",
             targets: ["_MatchingEngine"]),
-        .library(
-            name: "_Unicode",
-            targets: ["_Unicode"]),
         .executable(
             name: "VariadicsGenerator",
             targets: ["VariadicsGenerator"])
@@ -31,7 +28,7 @@ let package = Package(
         // Targets can depend on other targets in this package, and on products in packages which this package depends on.
         .target(
             name: "_MatchingEngine",
-            dependencies: [/*"_Unicode"*/],
+            dependencies: [],
             swiftSettings: [
                 .unsafeFlags(["-enable-library-evolution"])
             ]),
@@ -44,18 +41,12 @@ let package = Package(
             swiftSettings: [
                 .unsafeFlags(["-enable-library-evolution"])
             ]),
-        .target(
-            name: "_Unicode",
-            dependencies: []),
         .testTarget(
             name: "RegexTests",
             dependencies: ["_StringProcessing"]),
         .target(
             name: "Prototypes",
             dependencies: ["_MatchingEngine"]),
-        .testTarget(
-          name: "UnicodeTests",
-          dependencies: ["_Unicode"]),
 
         // MARK: Scripts
         .executableTarget(