Reset cache for the direct endpoint to the review when editing one (bug 987557)

This is needed because the ratings._rewriter below only works for the
app=slug, user=mine endpoint, and reviewers use the direct URI to the
review instead.
Merge pull request #429 from diox/fix-reviewers-rating-edit

Reset cache for the direct endpoint to the review when editing one (bug 987557)
fix potatolytics (bug 991306)
add regions for bug 9876806
use native persona if it is available
add navigator.mozId to capabilities
Merge pull request #443 from dethe/add_regions

add regions for bug 9876806
Revert "add navigator.mozId to capabilities"

This reverts commit 661cf0688abf0b3a2170ab057f60cf7733aac607.
fix settings typo
fix marketplace.js with mozid
only try mozID on firefoxos
fix caps.persona
Define media_url for Travis to emulate having a CDN (bug 997942)
cdn_url is automatically set from media_url if it exists (bug 997942)
Fix flaky unit test by mocking what's necessary (bug 997942)
Change the default pagination to 10 results instead of 25 on mobile (bug 997793)