post dynamic variables for texttospeach module

Since I needed to be able to dynamically generate the text to be read (on a PHP url source), and that text depends on some variables of that call, I added support to send asterisk variables over POST on dynamic url sources .. This is very usefull when you are dynamically generating the text using PHP or other similar language ..

I added in the URL configuration a field named "Dynamic AGI Variables", you insert the variables you want to send separated by a comma, for example: "agi_callerid,agi_language"
You can also add dynamic variables set by other applications, like a DTMF input.
The variables are passed over POST to the PHP (or whatever) file specified in the URL field.

This is very very usefull when combined with some DTMF input or the "dynroute" module (http://www.voipsupport.it/pmwiki/pmwiki.php?n=Freepbx.DynamicRouting)

I think it would be a very useful feature on the main branch of this module :)

Regards
Gabriel