update build tool
add style guide
Merge branch 'testing' into integration_merge

Conflicts:
	app/build.gradle
	app/src/main/java/com/clarityhk/goodcity/activities/IntroductionActivity.java
	app/src/main/res/layout/activity_introduction.xml
	app/src/main/res/values/colors.xml
	app/src/test/java/com/clarityhk/goodcity/test/DummyTest.java
Merge pull request #3 from clarityhk/integration_merge

Integration merge