Add testing infrastructure using jest

Added simple test to illustrate how to use jest with react.

app/components/__tests__/EntrySelector-test.jsx

@@ -0,0 +1,17 @@
+jest.autoMockOff()
+
+import React from 'react'
+import ReactDOM from 'react-dom'
+import TestUtils from 'react-addons-test-utils'
+
+const EntrySelector = require('../EntrySelector').default
+
+describe('EntrySelector', () => {
+
+    it('test jest', () => {
+        var entrySelector = TestUtils.renderIntoDocument(
+            <EntrySelector id="entry-selector" className="left inline fill-height" />
+        )
+        expect(entrySelector.state.entries.length).toEqual(0)
+    })
+})