Handle Entrypoint and Cmd correctly
Handle Entrypoint and Cmd correctly

Use Entrypoint + Cmd when both are present or just Cmd when Entrypoint
is not present.

Since non-absolute paths are not allowed by the spec, if the resulting
command is not absolute we fall back to running it with "/bin/sh -c".

jsoriano/docker2aci,ChengTiesheng/docker2aci,appc/docker2aci,OMWAVE/docker2aci,iaguis/docker2aci,jsoriano/docker2aci,mclarkson/docker2aci,vishvananda/docker2aci,dgonyeo/docker2aci,endocode/docker2aci,dgonyeo/docker2aci,OMWAVE/docker2aci,sgotti/docker2aci,vishvananda/docker2aci,pquerna/docker2aci,appc/docker2aci,jonboulle/docker2aci,jumpstarter-io/docker2aci