Adds basic support for the Swift programming language

Text only lexer for now until Pygments catches up

samples/Swift/section-53.swift

@@ -0,0 +1,12 @@
+class NamedShape {
+    var numberOfSides: Int = 0
+    var name: String
+
+    init(name: String) {
+       self.name = name
+    }
+
+    func simpleDescription() -> String {
+       return "A shape with \(numberOfSides) sides."
+    }
+}