CLI: Add support for project templates

Summary:
Currently it is not trivial for people to get started with React Native. `react-native init MyApp` just creates a simple app with a single screen. People have to spend time figuring out how to add more screens, or how to accomplish very basic tasks such as rendering a list of data or handling text input.

Let's add an option: `react-native init --template navigation` - this creates a "starter" app which can be easily tweaked into the actual app the person wants to build.

**Test plan (required)**

- Checked that 'react-native init MyApp' still works as before:

<img width="487" alt="screenshot 2017-02-02 16 56 28" src="https://cloud.githubusercontent.com/assets/346214/22559344/b2348ebe-e968-11e6-9032-d1c33216f490.png">

<img width="603" alt="screenshot 2017-02-02 16 58 04" src="https://cloud.githubusercontent.com/assets/346214/22559370/c96a2ca6-e968-11e6-91f7-7afb967920fc.png">

- Ran 'react-native init MyNavApp --template'. This prints the available templates:

```
$ react-native init MyNavApp
Closes https://github.com/facebook/react-native/pull/12170

Differential Revision: D4516241

Pulled By: mkonicek

fbshipit-source-id: 8ac081157919872e92947ed64ea64fb48078614d

local-cli/runAndroid/runAndroid.js

@@ -193,7 +193,7 @@ function runOnAllDevices(args, cmd, packageName, adbPath){
     }
 
     console.log(chalk.bold(
-      `Building and installing the app on the device (cd android && ${cmd} ${gradleArgs.join(' ')}...`
+      `Building and installing the app on the device (cd android && ${cmd} ${gradleArgs.join(' ')})...`
     ));
 
     child_process.execFileSync(cmd, gradleArgs, {