bugfix ratio calc
new vcf sites gen step
corrected required Redis version to 2.6, not 2.6.5; noted that the server should run on a node that can ssh to all others without a password
Net::SSH is no longer required
added new ssh() method to do sshing better than Net::SSH
use BackEnd->ssh instead of other ssh methods
Merge branch 'develop' of /software/vertres/git/origin/vr-pipe into feature/ec2