helping action-sendmessage to consider additional parameters

Hi,

It seems to me that many users really look for a feature to create a new tiddler via a message. Naturally they want to specify a template and add some variables.

Two plugins I know picked up this issue.

Stephan's plugin: https://groups.google.com/d/msg/tiddlywiki/EbTVXUrWss4/Wwg57Zmur2YJ
Matabele's plugin: https://groups.google.com/d/msg/tiddlywiki/sLYQCaTVRVA/hUqi9nx-c-YJ

However with the modification in the action-sendmessage.js it can be done very easily(!) without a plugin(!) and without much code change(!):

I can now do the following to create a new tiddler via a button and set some fields and a title:

    Create a new tiddler named "helloworld!" and based on a tiddler called "skeleton" also give it a field "bla" with value "hi"

    <$button>
    <$action-sendmessage $message="tm-new-tiddler" $param="skeleton" title="test"  bla="hi" /> create a new tiddler!
    </$button>