Revert "remove fbsimctl"

This reverts commit 082a65d791.

.travis.yml

   - source ./scripts/env/installNode.sh
         # android sdk:
   - source ./scripts/env/installAndroidSDK.sh
+        # fbsimctl:
+  - source ./scripts/env/installFbSimCtl.sh
 
 script:
   - set -e

CONTRIBUTING.md

 curl --location https://dl.google.com/android/android-sdk_r24.4.1-macosx.zip | tar -x -z -C $HOME
 ```
 
+* fbsimctl:
+
+```
+export CODE_SIGNING_REQUIRED=NO
+brew tap facebook/fb && brew install fbsimctl
+```
+
 ## Basics - Getting Started
 
 Got your environment set up? Go ahead and clone the repo. (Fork it first so you can open a PR when you're ready.)

scripts/env/installFbSimCtl.sh

+#!/bin/bash -e
+
+brew tap facebook/fb
+brew install fbsimctl

scripts/test.e2e.ios.js

 }
 
 function run() {
+  if (!exec.which(`fbsimctl`)) {
+    throw new Error(`fbsimctl must be installed: "brew tap facebook/fb && brew install fbsimctl"`);
+  }
   buildProjForDetox();
   e2e();
 }