Fix nstrcmp() to prevent ifconfig from showing duplicate interfaces.

Patch from TAKADA Yoshihito
https://bugzilla.redhat.com/show_bug.cgi?id=1021109
Fix serveral strings in de/fr/pt_BR.po

RHBZ#1032563
netstat.c: fix typo in error message
Add netstat -S/--sctp parameter into help and manpages
Fix unsigned sscanf format

After coverity tool scan, some warnings about signed/unsigned conflicts in
sscanf format string were found. Not a serious problem, but better to be
correct.
Documented metric defaults, made markup of keywords/variables more consistent.
fix default for inet4 (0) and pointer to ip(8)