Add simple virus and spam posts filter script, by Joschi <mail@dh1jc.de>

"Hey,

added a simple line for CLAMDSCAN and SPAMC to filter at least simple virus and spam posts...

Seems to work EICAR/GTUBE tested...

[syslog]
Mar 16 13:51:41 v22014012004216674 logger: snntpd.bin:SNPOST:Message contains virus ( Eicar-Test-Signature FOUND ) and is rejected
Mar 16 13:51:41 v22014012004216674 logger: snntpd.bin:do_post:SNPOST died with 9
Mar 16 13:56:05 v22014012004216674 logger: snntpd.bin:SNPOST:Message is considered as SPAM (1001.2/5.0) and is rejected
Mar 16 13:56:05 v22014012004216674 logger: snntpd.bin:do_post:SNPOST died with 9

If you like, add it to your git ..
[note: you must have a running clamav daemon and spamassasin running...]"
Merge branch 'master' of github.com:liu-chong/sn