add mobile poster image feature for video and background_video pages
Merge pull request #143 from schoetty/mobile_poster

add mobile poster image feature for video and background_video pages
Move spec support files into config and helpers directory

`config` contains configuration of testing libraries. `helpers`
contains doubles and modules mixed into example groups.
Run specs against generated rails app

Add `pageflow-support` gemspec to be used by Pageflow extension
gems. Use `Pageflow::Dummy` to generate dummy test application of
different Rails versions.
Remove dummy app
Use Instafail RSpec formatter
Fix factory girl deprecation warning.

`ignore` is now `transient`.
Fix RSpec version

Tackle deprecation warning generated by 2.99 for update to 3.0 later.
Skip schema:load in travis build
Ignore missing db on db:drop