sngrep: new package

sngrep: new package

sngrep is a tool for displaying SIP calls message flows from terminal.
It supports live capture to display realtime SIP packets and can also
be used as PCAP viewer.

Signed-off-by: Adam Duskett <aduskett@codeblue.com>
[Thomas:
 - ncurses wide char and other sub-options are not needed to build
   sngrep, so they are removed, as well as the wchar
   dependency. ncurses with wchar support is only needed when
   --enable-unicode is passed, but even then, it doesn't work because
   the configure script searches <ncursesw/ncurses.h>, so unicode
   support has been explicitly disabled.
 - add optional dependencies on OpenSSL, GnuTLS and PCRE. This also
   makes sure they are explicitly enabled/disabled depending on the
   configuration.
 - add upstream URL in Config.in file.]
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>