Do not default to verbose debug in the REPL.
Fix bug where DList.apply can't be too short.

Fix bug that occurs when using DList.apply with a resulting DList whose
length is shorter than the the hinted number of map taks.
Make REPL 'ls'/'cat' support multiple filesystems.

Add support to the Scoobi REPL's 'ls' and 'cat' commands to support
multiple filesystems, that is, not just the "default" filesystem as
specified in the configuration. The fileystem will be inferred from the
URI, else will default to what is specified in the configuration.