upload webdriver for MacOS 64bit
when I run ant in eclipse I had to set Absolute path
增加Excel数据驱动方法ExcelDataProvider.java
增加Excel测试demo：GoogleSearchWithDataDriver.java
增加Excel操作包：jxl.jar
增加测试数据
Merge pull request #13 from chenDoInG/master

本次Merge内容包括：
- 来自`chenDoInG`的`增加Excel数据驱动方法,jar,测试类`【代码已Review，质量很赞】
- 来自`朱元杰`的对于`Safari`浏览器的支持【虽然在BrowserEmulator启动模式中加入了对于Safari的支持，但各个API是否确实可以在Safari下正常运行，还待观察】
- 在feature分支上的图像对比功能
- 其它一些misc改动
[misc]更新.classpath
Update ImageContrast.java

math bug fixed.
Merge pull request #15 from croath/master

Update ImageContrast.java
Update README.md about how to contribute to Dagger
Merge pull request #18 from NetEase/master

Merge recent accepted commits from master to develop.
Merge branch 'develop' of https://github.com/NetEase/Dagger