Better Entrypoint Support

[mhamrah]

In order to address #410 I'd like the ability to specify entrypoint parameters. This adds a new setting, dockerEntrypoint, which takes in a Seq[String] and passes that to the ExecCmd form "ENTRYPOINT". It keeps the default bin/executableScriptName in place.

On a sidenote, I don't understand the current usage of executableScriptName. This does change the entrypoint value, but it forces the script to be places in /opt/docker/bin. It also doesn't change the outputted bin script's name. So it seems you need a specific script in a specific place in your container. I believe passing an ENTRYPOINT exec value is a more flexible approach.

Tests/documentation coming, but I wanted to get early feedback.

Thank you,

Mike

[mhamrah]

I also have no idea what the deal is with the scalariform stuff, thus the two commits.

[muuki88]

Looks like a valid use case to me (see discussion in #410 )

@fiadliel if you don't have any objections, feel free to merge.

[fiadliel]

LGTM (but I can't merge).

[muuki88]

@jsuereth, @fiadliel needs merge rights :)