Win: Generation of paths in the CSS

The windows system uses a forward slash "\" to separate directories in linux using a backslash "/".
The result is that the output is CSS like:

.ui-widget-shadow { margin: -8px 0 0 -8px; padding: 8px; background: #aaaaaa url(\web\static\lib\jquery.ui\css\smoothness/images/ui-bg_flat_0_aaaaaa_40x100.png)

Then, when this line comes as a GET-request is perceived as a sequence of ESC.
The final address by which we seek the file looks like - /addons/web/statis/webstaticlibjquery.uicsssmoothness/images/ui-bg_flat_0_aaaaaa_40x100.png

Workaround:
file: addons\web\controller\main.py
Class WebClient
def css
     def reader
               web_dir = os.path.dirname(web_path)
+ web_dir = web_dir.replace('\\', '/')