Audit Log interface, schema, and cassandra implementation

More audit log stuff.

More audit logging work

Audit log tests and docs
scheduler system test scenarios
test for mutiple policies to execute at the same instance
skipping cron tests
refactor the header validation, setup and using constants
changes fetch url from config for dev and preprod
changes to links test
clean up scripts
changes to server metadata
negative test time.now
updated cloudcafe version
in Additional Resources, add suggestion to see GitHub repo
manisht reviews + negative test for update policy type
adding more cooldown validations

clean up within scripts
skip the cron tests
change to create_at_style and unskipped cron tests
Merge branch 'master' of github.com:rackerlabs/otter into TWrose
in API Operations chapter, standardize major section titles: x.x Groups, Configurations, Policies, etc (not Group Resources etc)
in General API Information chapter, add annotated examples of authentication credientials and service catalog response
Checkpoint supervisor refactor.