yy
Merge remote-tracking branch 'origin/master'

Conflicts:
	projects/DrawingBoard/app/src/main/AndroidManifest.xml
	projects/DrawingBoard/app/src/main/java/cn/edu/shu/android/group6/drawingboard/app/MainActivity.java
	projects/DrawingBoard/app/src/main/java/cn/edu/shu/android/group6/drawingboard/app/WelcomeActivity.java
yy