Added tests for mock and dockerclient to ensure they implement the Client interface
More explicit errors on TLS failure.

When getting an HTTP connection error different than connection refused,
issue a warning about connecting to TLS enabled daemons with no
TLSConfig, similar to what the Docker CLI is doing.

Signed-off-by: Andrea Luzzardi <aluzzardi@gmail.com>
Merge pull request #54 from aluzzardi/tls-config-check

More explicit errors on TLS failure.
Merge pull request #53 from epipho/iface-test

Added test to prevent not updating interface/mock/dockerclient
move mock to it's own pkg
Merge pull request #58 from vieux/move_mock

move mock to it's own pkg
Add exec method
Merge pull request #48 from donhcd/addExec

Add Exec method
Add better error handling for PullImage