Display current review in "other sub-s" (#143)

If current user has a review for a submission, display its content in a
review form and disable that form.

Fixes #143
Fixing pep8 warnings.
Reduced the amount of duplicated code

part of #143.
A cron job to fix parameter values' discrepancy.

Part of #136.
Merge remote-tracking branch 'upstream/master' into solvers_num
Merge remote-tracking branch 'upstream/master' into own_review
Reacting to code review (#143)
Reacting to code review (part of #136.)
Merge remote-tracking branch 'upstream/master' into solvers_num
Showing other people's reviews

if thissubmission was already reviewed by the current user.

Part of #143.
Merge remote-tracking branch 'upstream/master' into own_review
Typo when settings a button class.
Fixing empty last page in attempts list

in "Review" tab.

Fixes #152.
Added paging for incoming jeeqs
handled un-logged user.
Reacting to code review-2 (#143).
added paging for feedbacks for a specific submission.
add pdf.min.js
delete unused files and directories under /static/pdfjs
Merge pull request #189 from anubhavsinha/#187_pdfjs_minified

add pdf.min.js
Merge pull request #183 from egor83/152_other_subs_last_page

Fixing empty last page in attempts list in "Review" tab. (fixes #152)