[FEATURE query-params-new] Hopefully final iteration

- default value'd QPs no longer show up in URL
- default value's type is used to determine how
  deserialized QPs are cast into controller prop values
- added queryParams Route config hash with properties
  `replace` and `refreshModel` to configure changed
  QP property behavior
- better code organization

/w @raytiley's help
Merge pull request #4468 from machty/query-params-v3

[FEATURE query-params-new] Hopefully final iteration
Merge pull request #4490 from rjackson/es6-ember-extension-support

ES6 ember-extension-support.
Merge pull request #4488 from rjackson/enable-ember-debug

Enable ember-debug to be loaded for non-prod builds.
ES6 ember-testing.