removed sqlite3, added pg gem
fixed database config
remove parallel gem

doesn't work with postgres. see
https://github.com/grosser/parallel/issues/62
Attempt at multithreading histogram generation

* Not sure if there's any improvement... rspec tests
  run at same speed

Conflicts:
	app/models/histogram.rb
Thread::Backtrace::Location fix for rbx
updated gemfile

rails 4.1.4 -> 4.1.9
foundation-rails -> 5.4.3.1 (for heroku)
add rails_12factor to gemfile
configure Tumblr in prod env
require rmagick in gemfile
require d3.js from cdnjs

fixes mixed content blocking