Windows path separator is invalid for urls

Files passed to the istanbul template are correctly copied but the path saved is a windows system path. This cause some problems in the browser and will often fail to give correct urls.

for example: "a\new\ball" will be interpreted as a `a` followed by a new line and followed by the `bell` character. Which will at some point cause a syntax error. 

This quickfix replace all "\" by "/" to form a valid url instead of a system path. This may affect many templates depending on this template. And might also be a source of problem for the windows platform.