Add support for certificate chains.

Add options (--ssl-chain-cert and --no-ssl-chain-cert) to control whether the argument to --ssl-cert is treated as a single certificate or a chain of certificates down to the root CA certificate.  Chained certificates are required by some browsers, including Firefox, in order to recognize some certificates.
Bump network and text
Merge pull request #52 from ryantrinkle/0.9-stable

Add support for certificate chains.
Merge branch '0.9-stable'

Conflicts:
	snap-server.cabal
	src/Snap/Http/Server.hs
	src/Snap/Internal/Http/Server.hs
	src/Snap/Internal/Http/Server/Config.hs
	src/Snap/Internal/Http/Server/TLS.hs