Remove dead stuff from ReadPromises

Move SetAuditVersion into ReadPromises
Rename variable ok -> policy_check_ok in generic_agent:ReadPromises
Pull REQUIRE_COMMENTS logic out of generic_agent:VerifyPromises

There's no verification in this.
Fix formatting in CheckConstraint
Remove global BODYPARTS, introduce PolicyCheckRunnable

Previously, referenced bodies from bundles where appended to the global
BODYPARTS list when calling CheckConstraint from the parser. These were
subsequently accounted for in generic_agent:VerifyPromises.

Now, PolicyCheck is split into PolicyCheckPartial and PolicyCheckRunnable.
PolicyCheckPartial verifies a partial policy, while PolicyCheckRunnable
verifies the integrity of a runnable policy. The latter now checks for
undefined bodies from the policy DOM alone.
Remove global SUBBUNDLES, use PolicyCheckRunnable
Merge pull request #338 from sigurdteigen/cleanup/runnable-policy-checks

Cleanup/runnable policy checks