CYB-292 Write script to start sidekiq, introduce foreman

* Sidekiq and clockworkd both now use tmp/log and tmp/pids
* new individual start scripts which are called by the Procfile

https://jira.ets.berkeley.edu/jira/browse/CYB-292
[nojira]  plugging more leaky state in the specs.
CYB-308 Gallery video URLs: users ending up with two gallery items for one submitted item

  * Canvas does not process or store file attachments if there is a URL given anyway, so
     instead do not deal with attachemnts if there is a URL for the submission.

https://jira.ets.berkeley.edu/jira/browse/CYB-308
CYB-311 - As a student, I wan to always have the option to change my sharing preference

https://jira.ets.berkeley.edu/jira/browse/CYB-311
Merge pull request #192 from coyote/more_plug_leaky_state_in_specs

CYB-315 plugging more leaky state in the specs.
Merge pull request #193 from coyote/thumbnails_for_videos_do_not_cache

CYB-308 Gallery video URLs: users ending up with two gallery items
Merge pull request #194 from christianv/CYB-311

CYB-311 - As a student, I want to always have the option to change my sharing preference
Merge pull request #189 from coyote/foreman_add

CYB-292 Write script to start sidekiq, introduce foreman