Add more unit tests for command_factory.

In particular for for task splitting commands and copying work dir outputs.
command_factory cleanup - introduce abstraction for more readable command construction logic.
command_factory cleanup - split big build_command method into smaller well-named pieces.
command_factory cleanup - a couple more small tweaks for readability.
Implement 'remote' dependency_resolution for LWR.

Set LWR destination parameter 'dependency_resolution' to remote. This will disable all dependency resolution on Galaxy side when building up command line and instead pass the tool's requirements along to the LWR server for resolution on that end. This requires a very up-to-date LWR server.

I think right now 'galaxy_packages' and 'modules' resolution would work but not 'tool_shed_package' resolution - I think more repository information related to the tool needs to be passed along to the LWR to enable this.

Updates the LWR client code through LWR changeset 4380e65 - mostly bringing in changes to enable this but also includes other small refactorings to stager.py.
Fill out job_conf.xml example with LWR options added over recent months.