Update pdf.js to support version 0.11 of pdf2htmlEX

Prior to version 0.11, pdf2htmlEX created three css files for each converted document:

```
base.css
fancy.css
lines.css
```

In version 0.11, pdf2htmlEX nows runs those files through YUI compressor and names them:

```
base.min.css
fancy.min.css
```

(more investigation needed for `lines.css`)

`pdf.js` should be updated to accommodate the new file names