Updated documentation

* added RVM option for single-user install
* clarified Web Server options
* bluepill sample config: create socket directory if it doesn't exist
* add multisite.yml.production-sample
* rename production.sample.rb (OCD)
* make two database.yml samples (one for dev, one for prod)
* fixed travis build (database.yml.sample renamed)
* fix other references to database.yml.sample
* clean up 'rvm requirements' instructions as per @mpapis
Merge pull request #900 from Supermathie/sysadmin-docs

Updated documentation
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'
Rewind the blob when reading