Order nightly before docs generation

[felixmulder]

Generated docs check out a different branch and removes everything in
the CWD

[felixmulder]

@smarter: going to leave for now, this is the script used from the server to deploy:

#!/usr/bin/env python2

from urllib2 import urlopen
import json
import os

endpoint = "http://dotty-ci.epfl.ch/api/repos/" + \
           "lampepfl/dotty/builds/latest?branch=master"
res = urlopen(endpoint)
data = res.read()
build = json.loads(data)

print "Deploying build number: ", build['number']

# execute deployment: drone deploy {org}/{project} {buildNumber} {target}
os.execvp('drone', [ 'drone'
                   , 'deploy'
                   , 'lampepfl/dotty'
                   , str(build['number'])
                   , 'nightly'
                   ])