Use chunked encoding when passing the docker image.

If you don't do this, you very often run out of heap space, as the
webclient will create a buffer for the entire image file (possibly
many gigabytes) before sending it.

Signed-off-by: Nigel Magnay <nigel.magnay@gmail.com>
Merge pull request #118 from magnayn/pr2

Use chunked encoding when passing the docker image.
Update CHANGELOG.md
Currently, the certificates present for SSL access must all be
accessible on the local disk. This is inconvenient for some clients
who may already have a pre-baked keystore in hand.

Create different options for retrieving the neccessary SSLContext,
so that the two different options can be used.

Signed-off-by: Nigel Magnay <nigel.magnay@gmail.com>
Change the client configuration so that it can optionally take an
SSLConfig.

Signed-off-by: Nigel Magnay <nigel.magnay@gmail.com>