add main activity
Merge remote-tracking branch 'origin/master'

Conflicts:
	app/app.iml
	app/build.gradle
	app/src/main/AndroidManifest.xml
	app/src/main/res/drawable-hdpi/ic_launcher.png
	app/src/main/res/drawable-xhdpi/ic_launcher.png
	app/src/main/res/drawable-xxhdpi/ic_launcher.png
	app/src/main/res/layout/activity_main.xml
	app/src/main/res/menu/main.xml
	app/src/main/res/values/dimens.xml
	app/src/main/res/values/strings.xml
	app/src/main/res/values/styles.xml