Path quoting is haphazard and fragile

[natefoo]

Exposed by the Galaxy startup tests that use a space in the galaxy root pathname, we had some bugs with path handling, which are addressed in #87.

However, the quoting is a bit scattered and haphazard. Part of the issue is that we use the same format vars for multiple purposes, only some of which are going to be part of the command line, which (currently) is the only thing that should be quoted. The working dir option for both process managers should not be quoted, and neither should the log path for supervisor, since these are not interpreted by a shell. We quote the data dir because it's used in a command line but not elsewhere. We don't quote galaxy_root because it's not used in any command lines, etc.

So we probably need a more structured way to denote what needs to be quoted and what doesn't. The simplest and cleanest solution may be to just split the command line format vars from the rest of the format vars.

Also, the GxIT session map path and tusd_path probably still need to be fixed.