Refs #464. Copied over the current default iframe and added a legacy example.
Refs #464. Document the legacy iframe/skin option.
Refs #464. Added a changelog entry advertising the legacy iframe option.
Refs #464. More documentation on version 1.0 skin behavior.
Refs #464. Add the legacy skin.
Merge pull request #464 from wymeditor/issue_464

Create a legacy iframe and update styling on the default