[backend] ensure that only one createrepo is running at the same time

so multiple instances (which consumes 2+GB RAM each) does not take server down
[backend] do not create repo in destdir

it is not usefull at all to have repo of mixture of f19,f20,el5,el6 packages
[cli] allow to build into projects of other users
[fronted] link username to fas
[frontend] correctly address lock variable
[frontend] update to jquery 1.11.0
[cli] correctly pass username
Automatic commit of package [copr] release [1.27-1].
[backend] - pass lock to Actions

addressing:
Process jobgrab:
Traceback (most recent call last):
  File "/usr/lib64/python2.7/multiprocessing/process.py", line 258, in _bootstrap
    self.run()
  File "/usr/share/copr/copr-be.py", line 103, in run
    self.fetch_jobs()
  File "/usr/share/copr/copr-be.py", line 96, in fetch_jobs
    ao.run()
  File "/usr/share/copr/backend/actions.py", line 66, in run
    rc, out, err = createrepo(os.path.join(path, chroot))
Automatic commit of package [copr] release [1.28-1].