Change the way to display file name

Replace "word-wrap" with "text-overflow", also adds a title to get the full name.

Before
![before](http://dl.dropbox.com/u/2402301/imgs/github/00-webui-aria2-before.png)


After
![after](http://dl.dropbox.com/u/2402301/imgs/github/01-webui-aria2-after.png)