Using cocoapods cache to speed up the build time

.travis.yml

@@ -15,13 +15,14 @@ addons:
     packages:
     - curl # Fix the codecov upload issue
 
+cache: cocoapods
+podfile: Examples/Podfile
+
 before_install:
     - env
     - locale
-    - gem install cocoapods --no-rdoc --no-ri --no-document --quiet
     - gem install xcpretty --no-rdoc --no-ri --no-document --quiet
     - pod --version
-    - pod setup --silent > /dev/null
     - pod repo update --silent
     - xcpretty --version
     - xcodebuild -version