Version bump to v0.9.1
Revert "update active model serializers to latest". This introduced a regression to the SiteCustomizations part of the admin section.

This reverts commit d4360798013e754e770f136eade711ae5de93fd1.
FIX: User stream was loading the same page over and over once you scrolled past 60
items.
Merge remote-tracking branch 'upstream/master'