When using the 'Long Text' field, preview/load the WYSIWYG/Text/PureText editor in the 'Structure' step of the Wizard when the user hits 'Apply changes'

When the user is using 'Static List', 'User', 'Group', 'Database List' fields and he configures them, any change is applied in the preview after hitting the 'Apply changes'.

Same should be for the 'Long Text' field when the user is changing the Editor type. For this field type, changing the number of rows works in the preview.

Reasons:

• consistency in behavior with the other field types and with other properties for the same field type;
• previewing the change will clarify the user about what 'Text', 'PureText', 'WYSIWYG' means, since these options are not descriptive at all (what's the difference between text and pure text, etc.);
• preserves the WYSIWYG feel for the wizard, imitating the look in the View mode;
• the user doesn't need to go to the View mode to see what those options are about.

Possible problems:

• maybe some performance issues?