1. add intro/feedback menu;
2. add intro flow when by selecting intro menu.
1. anno in anno from community is 2-level now.
1. change anno home menu label from 'Quick Start' to 'Intro';
2. change anno home menu to 'Intro', 'Feedback' and 'Settings'.
detect 4 spiral gesture and increase accuracy.
Merge branch 'community_level'
Merge branch 'gesture'
merge CommunityActivity.java
merge gesture.