Fix @author tag to prevent name craziness.
Refactor surround code to use a target-delimiter object.
Add imlementation of dynamic delimiter holder for XML tags.
Implement 'ReplaceDelimiterMode'.

This mode will show the minibuffer in which the user can enter a new delimiter, like an xmltag or LaTeX tagblock.
ChangeDelimiterCommand can now change to ReplaceDelimiterMode.

In this case the replace only takes place when the ReplaceDelimiterMode has exited.
[cs/y]s*[t/<] motions now trigger ReplaceDelimiterMode for xml tags.
Remove count from AbstractDynamicDelimiterHolder's update method.
Allow dynamic delimiter templates based on previous text contents.