New features:
 - classes promises now take an optional scope constraint.
 - new built-in functions: every, none, some, nth, sublist, uniq, filter
    classesmatching, strftime, filestat, ifelse, maparray, format
 - cf-promises flag --parse-tree is replaced by --policy-output-format=, 
    requiring the user to specify the output format (none, cf, json)
 - cf-promises allows partial check of policy 
    (without body common control) without integrity check;
   --full-check enforces integrity check
 - agent binaries support JSON input format (.json file as generated 
    by cf-promises)
 - cf-key: new options --trust-key/-t and --print-digest/-p
 - Class "failsafe_fallback" is defined in failsafe.cf when main 
    policy contains errors and failsafe is run because of this
 - add scope attribute for body classes (Redmine #2013)
 - Better diagnostics of parsing errors
 - Error messages from parser now show the context of error
 - new cf-agent option: --self-diagnostics
 - new output format, and --legacy-output
 - warnings for cf-promises.
 - Enable zeroconf-discovery of policy hubs for automatic 
    bootstrapping if Avahi is present
 - Support for sys.cpus on more platforms than Linux & HPUX