The urlcatcher demonstrates how to open a URL embedded in SDP
when a call comes in, like the webconference application does.
This way, e.g. a conference control web page can be shown which
allows to list participants, dial in further users etc.
How to use it:
o register your SEMS at some registrar with reg_agent
o direct calls to urlcatcher (application=urlcatcher)
o call yourself from https://webconference.iptel.org or your
own web interface