Describe server loading options in server docs

Wanted to document options for overriding the default server loader as per #376. I've already signed the typesafe CLA, but maybe not for sbt-native-packager.
I agree and will make the change. It will also tighten up the
documentation.

On Fri, Oct 17, 2014 at 6:31 AM, Gary Coady <notifications@github.com>
wrote:

> In src/sphinx/GettingStartedApplications/AddingConfiguration.rst:
>
> > @@ -130,5 +130,20 @@ One means of doing this is hooking the ``batScriptExtraDefines`` key.  This allo
> >
> >  Now, the windows version will also load the configuration from the ``conf/`` directory of the package.
> >
> > +More Complex Scripts
> > +--------------------
> > +
> > +As you read earlier the ```bashScriptExtraDefines``` sequence allows you to add new lines to the default bash script used to start the application.
> > +This is useful when you need a setting which isn't mean for the command-line parameter list passed to the java process. The lines added to
> > +```bashScriptExtraDefines``` are placed near the end of the script and have access to a number of utility bash functions (e.g. ``addJava``,
> > +``addApp``, ``addResidual``, ``addDebugger``). You can add lines to this script as we did for the Typesage config file above. For more complex
> > +scripts you can also inject a seperate file managed in your source tree or resource directory: ::
> > +
> > +    bashScriptExtraDefines := Source.fromInputStream(this.getClass.getResourceAsStream("/setup-env")).getLines.toSeq
>
> I think it's better to recommend appending to this setting, in case some
> other plugin wants to add its own (hopefully compatible) lines.
>
> Also, it seems like it might be more consistent to make use of the same IO
> library throughout the examples, and sbt.IO is used in the next example.
>
> An alternative (untested) could be:
>
> bashScriptExtraDefines ++= IO.readLinesURL(this.getClass.getResource("/setup-env"))
>
> —
> Reply to this email directly or view it on GitHub
> <https://github.com/sbt/sbt-native-packager/pull/379/files#r19010987>.
>