Refactor common parts into slingsby.general.utils

Also properly handle SSH mocking in dev, enabling "file uploads" to be
tested.
Make nginx log to /var/log/nginx
Remove pip state and refactor
Split www user to separate users for uwsgi and nginx
Move slingsby nginx site into slingsby state
Make slingsby state standalone
Nuke old tasks app
Add a new vm to act as fileserver
Add new archive

Images are resized and uploaded along with the original to the fileserver
asyncronously. Old Zoombox have been replaced with blueimp-gallery, tests
have been added (although not very thorough), the model layout have been
similified (no more galleries, just events with a bunch of images, each
image has a photographer, and capture time is extracted from EXIF for
sorting). The entire thing works also without JS, both for legacy
browsers, or if something crashes.

Note that viewing the images locally requires a running "server", 'python
-m SimpleHTTPServer 8001' in the media dir will do.
Update the readme
Silence tests, and stop on first failure
Downgrade pycrypto to 2.6

Makes it easier for windows users since this is the version that is
available as a pre-compiled binary.