allow non ts files to be passed in to the compiler

src/compiler/parser.ts

@@ -4328,7 +4328,7 @@ module ts {
             }
             var diagnostic: DiagnosticMessage;
             if (hasExtension(filename)) {
-                if (!fileExtensionIs(filename, ".ts")) {
+                if (!options.allowNonTsExtensions && !fileExtensionIs(filename, ".ts")) {
                     diagnostic = Diagnostics.File_0_must_have_extension_ts_or_d_ts;
                 }
                 else if (!findSourceFile(filename, isDefaultLib, refFile, refPos, refEnd)) {

src/compiler/types.ts

@@ -1152,6 +1152,7 @@ module ts {
         version?: boolean;
         watch?: boolean;
         preserveConstEnums?: boolean;
+        allowNonTsExtensions?: boolean;
         [option: string]: string | number | boolean;
     }