changed session to :cookie_store
updated config name in secret_token.rb
removed final transition gem (activerecord-session_store)
added line in README w/ secret key instructions
made the e-mail links instructions one line (it's Markdown, not Ruby)
updated Gemfile.lock
Merge branch 'master' into 880_session_cookie

Conflicts:
	Gemfile.lock
	README.md
Merge pull request #995 from YaleSTC/880_session_cookie

resolves #880