new 404 page,  solved contact page

#16 
#19 
This is a nice touch, but it also means that for every 'Page not found', we have to query our db to get the values: commits, users, lines, which adds a lot of stress to it.

The 'Update 404 page' issue just wanted clean this page from lines like 'a(href="/projects") Projects' which are part of another project and should not appear here. It would also be good addition if it could extend the base layout.jade file, so further changes there propagate here as well.