initial type revision
add basic metadata
constraint: add simple validation
constraint/resource: support array values
initial spec tests and Gemfile for appropriate bundle
add .travis.yml for CI spec tests
bundle: add puppet for successful CI
README: link travis status
README: syntax fixes in examples
constraint: more validation and spec cleanup
spec: add some initial syntax examples
constraint: call fail from #validate instead of raising manually
constraint: rename #in_valid_catalog?, raise instead of returning

The semantics of the check method should mirror the validate hook more
closely. It has been found during PR triage that the method name was
clunky, the new name is supposed to fit a wider range of possible uses.
constraint: call #prerun_check from autorequire

Simple hack to allow constraint semantics to work with current agent versions.
prepare for release by making version compliant
fix syntax examle in Modulefile
constraint/properties: more validation and tests