Add extraChainFile option to ports file.

Hooray for hynek
Create startcom-chain.pem

ca.pem and sub.class2.server.ca.pem retrieved from https://www.startssl.com/certs/
add sub.class1.server.ca.pem while we're at it
Merge pull request #5 from glyph/chain-certificate

Add chain certificates to stop popping a cert warning on new visitors' browsers.