Add support for config file loaded from $OPENSHIFT_DATA_DIR/config.json on startup

There is currently a single config option which specifies
whether to use SSL by default when retrieving domain icons.

As discussed in https://github.com/robertknight/passcards/issues/19 ,
there are many sites whose homepages have broken SSL configurations.

When the server is being run from rhcloud (as opposed to locally),
it may be preferable to fetch icons via HTTP by default.
Roll passcards update