Add 3 Yokogawa SCADA vulns

These represent our part for public disclosure of the issues listed
here:

http://www.yokogawa.com/dcs/security/ysar/YSAR-14-0001E.pdf

Yokogawa is calling these YSAR-14-0001E, and I think that they map
thusly:

YSAR-14-0001E Vulnerability 1 :: R7-2013-19.1
YSAR-14-0001E Vulnerability 2 :: R7-2013-19.3
YSAR-14-0001E Vulnerability 3 :: R7-2013-19.4

@jvazquez-r7 if you could confirm, I'd be delighted to land these and
get your disclosure blog post published at:

https://community.rapid7.com/community/metasploit/blog/2014/03/10/yokogawa-centum-cs3000-vulnerabilities

Thanks for all the work on these!
Use nick instead of name
Change DoS module location
More nick instead of name
Land todb-r7#13 for rapid7#3081 credit update
Land #3081, Yokogawa SCADA vulns

I know it looks like I'm landing my own PR, but it's an illusion; I am
merely shoving bits around on @jvazquez-r7's behalf while he is
technically (and now actually) on vacation.