make warning and error different

The warning and error is the almost same before
![2014-03-14-174848_770x184_scrot](https://f.cloud.github.com/assets/1137238/2419455/de6c5ae4-ab5d-11e3-8de1-37766e8fdc7e.png)

After, it can see the error easily
![2014-03-14-175420_756x182_scrot](https://f.cloud.github.com/assets/1137238/2419498/a4fc96a6-ab5e-11e3-8a5d-791ba1dd7bea.png)