Fix this in harness and improve gulpfile defaults

Author: sandersn

Gulpfile.ts

@@ -306,6 +306,9 @@ function needsUpdate(source: string | string[], dest: string | string[]): boolea
 
 function getCompilerSettings(base: tsc.Settings, useBuiltCompiler?: boolean): tsc.Settings {
     const copy: tsc.Settings = {};
+    // TODO: Add --noImplicitThis --types --pretty when gulp-typescript adds support for them
+    copy.noImplicitAny = true;
+    copy.noEmitOnError = true;
     for (const key in base) {
         copy[key] = base[key];
     }

src/harness/harness.ts

@@ -127,7 +127,7 @@ namespace Utils {
     export function memoize<T extends Function>(f: T): T {
         const cache: { [idx: string]: any } = {};
 
-        return <any>(function() {
+        return <any>(function(this: any) {
             const key = Array.prototype.join.call(arguments);
             const cachedResult = cache[key];
             if (cachedResult) {