Rename tails warning header for consistency.
Force ok_json instead of the json_common MultiJson adapter
Merge pull request #1051 from heroku/pedro-force-ok-json-adapter

Force ok_json instead of the json_common MultiJson adapter
v3.5.1
Revert "Force ok_json instead of the json_common MultiJson adapter"

This reverts commit 6fe67aaf4380b41f14ce14576cc4dabfd0a60fd1.
v3.5.2
Revert "Merge pull request #887 from heroku/multi_json"

This reverts commit edf72a00caa4a642bd3b88e152a66b7b0aa6a63b, reversing
changes made to fd73503abdd949f095b09b837c5e41ad9ed5eb38.

Conflicts:
	lib/heroku/helpers.rb
v3.6.0
Allow rakefile to load without test gem group.