Extend -tag option to use style templates

Extend -tag option to use templates that determine
what the text will look like.
The syntax would be something like:

   -tag todo:a:"To Do:":ParamTemplate

This means that users would be able to create more
complex custom tags with the -tag option.
The SimpleTaglet format would be the default,
which they could override by specifying a fourth
term to -tag.

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