[asterisk-ss7] M3UA additions in libss7

[Paul Bagyenda]

Hi,

  We have some mods to  add M3UA (ASP mode) over SCTP to libss7. Also  
included are minor mods to pass other MTP user part messages up to the  
processing module (whatever that may be).

  This is a first stab, so things may break. It however passes tests  
implemented by the M3UA test tool found here: http://sctp.fh-muenster.de/m3ua-testtool.html

  If there is interest, we are happy to add this to libss7

Paul.