Validate the shortest certificate chain (#84)

Validate the shortest certificate chain (#84)

Do not download remote certificate for issuer X if the received server
certificate (signed by X) can be validated using a locally available CA
certificate. According to our tests, a typical browser does not follow
'CA Issuers' references to download 'missing' certificates when the
browser can validate the origin server certificate (or its chain) using
a local CA certificate. Avoiding unnecessary validations and downloads
not only saves time, but can prevent validation failures as well!

This is Measurement Factory project