set target sdk to API 19(Kitkat)
add Weibo sdk lib, and finish authentication code
Merge remote-tracking branch 'origin/master'

Conflicts:
	LingBo/LingBo.iml
	LingBo/src/main/AndroidManifest.xml
	LingBo/src/main/java/com/freewine/lingbo/WeiboListActivity.java
	LingBo/src/main/java/com/freewine/lingbo/WeiboListFragment.java
	LingBo/src/main/res/layout/activity_weibo_list.xml
	LingBo/src/main/res/menu/main.xml
	LingBo/src/main/res/values/strings.xml