FS-5498 add profile-variables section to directory to specify profile variables to be set automatically

Added mod_rayo (XMPP 3PCC http://xmpp.org/extensions/xep-0327.html). Used by Adhearsion as its native call control protocol.  Currently beta testing.

This is needed for correctly setting the default storage directory for
Debian builds.

add some device-state mechinism to FS to allow tracking of device-specific states where they may have more than one call from the same device

It seems I cannot contact the original author
it seems has a bug which even cannot compile with mp4v2-trunk-479
This patch allow it to compile

Without this dependency we might not end up with sendmail installed
which would be unnecessarily surprising when using mod_voicemail.

When vm-storage-dir was set to an absolute path, FS would abort after
delivering a VM because we were trying to free(3) memory sitting in
the middle of a memory pool.

FS-5329

At this point we never want someone running a module against a
different version of FS than the module was built for.  It's also
conceivable that you could want to use the modules with libfreeswitch1
even if you weren't running FS itself.