Add documentation for BOSH drain scripts.
Minor edits
Merge branch 'mmb-drain-script'
Adding new bosh snapshots topic
remove escape character '\' from code classes
add 'Log Rotation' section to bosh/job-logs.html
reword 'Log Rotation' section in bosh/job-logs.html
change .log to  in Log Rotation section of job-logs.html
add necessary BOSH security group access rules to deploy-microbosh-to-aws.html
removed unncessary echo
persistent disks & disk pools
Merge pull request #22 from cloudfoundry/disk_pools

Introducing disk pools
edit terminology.html
edit deployment-manifest.html
Correcting typos and confusing sentence
edit persistent disk topic
edit persistent-disks.html
edit persistent-disks.html
edit persistent-disks.html
removed whats new section

Changelog is kept in bosh github repo: https://github.com/cloudfoundry/bosh/blob/master/CHANGELOG.md