#2 Added help for text formatting: italic, bold, bold italic

[xynyx]

I missed a feature until I realized that it was implemented but not properly documented. So I extended the Wiki Formating Demo.
THX for ''wiki in a jar'' :-)

[xynyx]

Added help for text formatting: italic, bold, bold italic

[rico_g]

Thank you for helping out! Your change will be in the next release.

Thanks again,
Rico.