fix(configuration): Allow more test file names

Appears my last change to leave this undefined breaks the integration tests.  It doesn't seem to break the real life behaviour of the package but that can be investigated some other time

src/JestTestRunner.ts

@@ -23,6 +23,7 @@ const DEFAULT_OPTIONS: Object = {
   setupFiles: [],
   snapshotSerializers: [],
   testEnvironment: 'jest-environment-jsdom',
+  testRegex: '(/__tests__/.*|(\\.|/)(test|spec))\\.jsx?$',
   testRunner: 'jest-jasmine2',
   verbose: true
 };