This unit test case reads a series of signatures from some binary files.
(These files were created with lo02-verifysigs), and then uses the public
keys saved to verify the signatures.
This validates that big public keys can be properly loaded from an ipsec.conf
file.

The public keys can be extracted from the *.secrets file using showhostkey,
using the "make update" target in the lo04-verifypubkeys test case.

The key/sig in 4096b came from peel.testing.xelerance.com. The private key
was not captured on purpose.
