Log Message:
Update netpgpverify and libnetpgpverify to 20160615:

Simplify the method of finding the end of the versioning information
in the signature - back up to the "\n" character at the end of the
signature start:

	"-----BEGIN PGP SIGNATURE-----\n"

and then find the "\n\n" character sequence to denote the start of the
signature itself. The previous version worked, but this is more efficient.