Allow to auto-generate self-signed SSL certificates

The setup is rather simple. Instead of a full-blown CA, a CSR is used to
create the self-signed certificate.
webui: Improve strings for volume type

"raw" and "local" were really suboptimal, and EqualLogic is a bit better
than EQLX.
Merge pull request #59 from saschpe/release/pebbles/master-ssl-gencerts

Allow to auto-generate self-signed SSL certificates
Merge pull request #60 from vuntz/improve-strings

webui: Improve strings for volume type
Fix keyfile being only defined, when using client cert

Use only client cert, when in use
Merge pull request #61 from asdil12/release/pebbles/master

Fix keyfile being only defined, when using client cert