Update 0.6 release docs with note on partner addresses
Backport release notes to CHANGELOG

Copying release notes from the 0.2, 0.3 and 0.4 branches.

Fixes #815
Correct INSTALLED_APPS note in docs

Turns out Django>=1.4 does include staticfiles and messages in its
default INSTALLED_APPS.

Fixes #814
Correct contributing link in README
Merge remote-tracking branch 'upstream/master'