By default verify presentation first and bail on failure before verifying VCs

[dlongley]

See FIXME: verify presentation first, then each individual credential
Commit: (40a5088) Fix reporting of credentialResults in verify output.
File: lib/index.js:435

It should still be possible to produce a verification log that checks everything, but default behavior should bail out early if the VP can't be verified to avoid checking all of the VCs thereafter as well.