Added some stuff for challenges
Merge branch 'master' of https://github.com/b2uproject/androidapp

Conflicts:
	b2u-mobileapp/b2u_mobileapp/bin/b2u_mobileapp.apk
	b2u-mobileapp/b2u_mobileapp/bin/classes.dex
	b2u-mobileapp/b2u_mobileapp/bin/classes/com/example/b2u_mobileapp/R$id.class
	b2u-mobileapp/b2u_mobileapp/bin/classes/com/example/b2u_mobileapp/R$layout.class
	b2u-mobileapp/b2u_mobileapp/bin/classes/com/example/b2u_mobileapp/R$menu.class
	b2u-mobileapp/b2u_mobileapp/bin/classes/com/example/b2u_mobileapp/R$string.class
	b2u-mobileapp/b2u_mobileapp/bin/classes/com/example/b2u_mobileapp/R$style.class
	b2u-mobileapp/b2u_mobileapp/bin/resources.ap_
	b2u-mobileapp/b2u_mobileapp/gen/com/example/b2u_mobileapp/R.java
	b2u-mobileapp/b2u_mobileapp/res/values/strings.xml
	b2u-mobileapp/b2u_mobileapp/src/com/example/b2u_mobileapp/ChallengeAdapter.java
	b2u-mobileapp/b2u_mobileapp/src/com/example/b2u_mobileapp/ChallengeInfoActivity.java
	b2u-mobileapp/b2u_mobileapp/src/com/example/b2u_mobileapp/ChallengeListActivity.java