M3UA support added (GH #342)

SCTP's payload protocol identifiers added.

M3UA tests provided by wireshark
http://wiki.wireshark.org/SampleCaptures#Sigtran_Protocol_Family
But RFC4666 tells that parameter 0x0002 aren't carried by M3UA, so
it's OK that tcpdump doesn't know about this identifier.

Conflicts:
	Makefile.in
	interface.h
	print-sctp.c
	sctpConstants.h

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The change to sctp_print() does three things:
* makes detection of ForCES consider PPID, not just port number
* verifies chunk length of all SCTP_DATA chunks, not just of ForCES
* adds PPID-specific dispatching with a particular case of M3UA

-- Denis
M3UA: improve code style

Merge m3ua.h into the only file that includes it (print-m3ua.c). Make
M3UA functions follow naming pattern, constify some of their arguments
and switch to ND_PRINT(). Make use of tok2str() and ternary conditional.
Eliminate declarations in the middle of code (C89).
M3UA: add safety checks

Add M3UA headers diagrams and check that message/parameter length allows
for at least respective header. Use TCHECK and signal malformed
structures.