Provides some minor modifications of Description2 plugin to meet our needs:

• #description2 parser hook shows the description as well as setting it to the page description.
• #description2hide parser hook hides the description and only sets it as the page description.
• Parses out [[SMW::on]] and [[SMW::off]] tags and interprets entities to allow |sep=,  and such.
• Converts <br/> tags to newlines, particularly for the non-hiding hook.