Install pods before building on Travis

Author: koke

.travis.yml

@@ -1,7 +1,10 @@
 osx_image: xcode8.2
 language: objective-c
+podfile: Example/Podfile
 notifications:
   email: true
 sudo: false
+before_script:
+  - cd Example && pod install && cd -
 script:
   - set -o pipefail && xcodebuild -workspace Example/EditorDemo.xcworkspace -scheme EditorDemo -sdk iphonesimulator | xcpretty