Merge pull request #890 from Sancus/master

[Fix Bug 989342] Let managers delete groups with a test to prove it.
Fix docs index
[fix bug 978998] Display 'Request to Join Group' for moderated groups.
[fix bug 992849] Remove unvouched users from groups.
Update flake8 conf and fix linting errors.

A pep8 / pyflakes update surfaced a few linting errors.
Merge pull request #894 from glogiotatidis/fixpep8

Update flake8 conf and fix linting errors.
Update mozillians-anonymize.sh

copy dev over
Merge pull request #896 from Sheeri/patch-10

Update mozillians-anonymize.sh
Merge pull request #893 from glogiotatidis/992849

[fix bug 992849] Remove unvouched users from groups.
[fix bug 931012] Internationalize some strings.
Change UserFactory to create vouched users by default.

Since the most common test scenario requires vouched users to work, I
switched UserFactory to vouch users by default. Also added parameter
'vouched' to easily explicitly control the vouch status.
Don't need to force ElasticSearch update after UserFactory.create().
[bug 978694] Tests for GraphiteMixin.

This wasn't added to the original commit, too many untracked files.
Merge pull request #888 from glogiotatidis/978694

[bug 978694] Tests for GraphiteMixin.
Merge pull request #871 from glogiotatidis/testscleanup

Clean up testcases
Cleanup templates.
Merge pull request #900 from glogiotatidis/templates

Cleanup templates.
[fix bug 990538] Beautify and cleanup group urls.
Merge pull request #885 from glogiotatidis/niceurls

[fix bug 990538] Beautify and cleanup group urls.
[Fix bug 703316] Update invite email