A lot going on in this commit: added cukes, refactored
api to add facade for multiple services.  This commit
is not final, and some more refactoring is coming soon.
support single argument to Args.notNull
Another helper class.
Refactor Endpoints
well, this escalated quickly
a few files were left out of the last commit
Delete old features.
Conjur: fix dumb mistake, add constructors, and make 
authn accessible.
It's called core, not directory!
Resource: Add injectable variables to context.
Change jaxb annotations to jackson.
JsonInject using class instead of id.
Dumb mistake.
Use Token.fromJson instead of default deserialization.
Add expiry, fix some serialization stupidness.
Integration tests.
Rename a file
More fiddling around with names.
Add account property to endpoints.
Fix an issue with Users.exists