make logDir and logUser customizable

we need to be able to mkdir on logDir and change the user that the logger runs as by default.

Ideally we would change the default logCommand to "multilog t ${logDir}" but I could not figure out how to set the default logCommand that may or may not use a default logDir.  So with this patch if if someone wants a custom logDir they will usually need to create a custom logCommand also.

-Cory