Adds basic support for the Swift programming language

Text only lexer for now until Pygments catches up

samples/Swift/section-83.swift

@@ -0,0 +1,8 @@
+func repeat<ItemType>(item: ItemType, times: Int) -> ItemType[] {
+    var result = ItemType[]()
+    for i in 0..times {
+         result += item
+    }
+    return result
+}
+repeat("knock", 4)