Adding a bunch of gulp utilities

This should allow a developer to write a gulpfile in TypeScript to
compile a TypeScript project.

gulp-typescript/gulp-typescript.d.ts

@@ -0,0 +1,38 @@
+// Type definitions for gulp-typescript
+// Project: https://github.com/ivogabe/gulp-typescript
+// Definitions by: Asana <https://asana.com>
+// Definitions: https://github.com/borisyankov/DefinitelyTyped
+
+/// <reference path="../node/node.d.ts"/>
+
+declare module "gulp-typescript" {
+    function GulpTypescript(params: GulpTypescript.Params, filters?: GulpTypescript.FilterSettings): GulpTypescript.CompilationStream;
+
+    module GulpTypescript {
+        export function createProject(params: Params): Params;
+        export function filter(filters: FilterSettings): CompilationStream;
+        interface Params {
+            declarationFiles?: boolean;
+            module?: string;
+            noEmitOnError?: boolean;
+            noExternalResolve?: boolean;
+            noImplicitAny?: boolean;
+            noLib?: boolean;
+            removeComments?: boolean;
+            sourceRoot?: string;
+            sortOutput?: boolean;
+            target?: string;
+        }
+
+        interface FilterSettings {
+            referencedFrom?: string[];
+        }
+
+        interface CompilationStream extends NodeJS.ReadWriteStream {
+            dts: NodeJS.ReadWriteStream;
+            js: NodeJS.ReadWriteStream;
+        }
+    }
+
+    export = GulpTypescript;
+}