optimize Gesture Lock

1. add more hint info
2. add animations for a better ux
3. change colors and styles
4. **backward compatibility support** for all versions of Android devices.

**EDIT** 
This PR uses a unofficial PreferenceFragment compatibility layer for Android 1.6 and up. In order to run the project in your IDE, please clone and add [this](https://github.com/haiwen/android-support-v4-preferencefragment) as a library project to your project.

**Warning**
**Please delete unused Gesture Lock relevant strings before start translating** 
Although this PR was titled as "optimize Gesture Lock", actually it deleted the "old" Gesture Lock totally and added a "new" one which has nothing to do with the "old". 
So there comes a problem due to the strings in "res/values/strings.xml" are not match.
In order to fix that, I already translated Chinese strings and English strings, which ensures the app runs properly on English and Chinese language devices. But problem occurs when goes to other language devices, the app may show English due to lacking of the needed strings.