remove hard system requires to allow "plugin" gems
  maintainers of adapter gems should be tasked with
  creating a file in the adapters folder instead of
  forcing a file to be present within AR-import adapters folder
  if `require` does not find a file in the first entry on the gem
  load path it will move on to the next, multiple folders that have
  adapters in them will be referenced instead of requiring that
  each adapter be registered withing AR-import, this is how
  AR has adapters that are dynamically loadable and do not
  require each adapter to be referenced in the AR gem
remove CREATE_DB in test_helper
Merge pull request #120 from abrandoned/master

let load paths determine which adapter is required a la activerecord adapters