File structure not navigatable on Firefox on Windows

[opyh]

Hey,

thanks for serve, it's a really cool tool! Just found one issue recently:

In Firefox on windows, links in the file structure view don't have their backslashes correctly replaced with slashes. The file view is not usable then.

To reproduce:

• use Firefox (I use 40) on Windows to access serve via http
• navigate into a directory from root (/build in my case)
• a '' is prepended to the URL (http://localhost:8000/%5Cbuild)
• navigate into a subdirectory in the new directory (in my case /build/dp)
• '' sneaks into the URL again, but this time escaped: http://localhost:8000/\build/\\build\dp\
• the server replies with an error message because the URL is not valid

[stevemao]

PR welcome @opyh