added in option to not strip conditional comments

I have attempted to add in the option to not strip conditional comments (the only thing i think is missing from this project)

BeautifulSoup doesn't seem to like conditional comments and ends up re-encoding the data between the two comments, hence the use of the ``fix_conditional_comments`` function

I think the only other thing i have missed in the django settings/integration but i just wanted to put this in to make sure its the right approach to take.