Clean up command line parsing.
Clean up command line parsing.

- Require additional k/v store parameters after the main one.
- Generalize handling when more than one k/v store is needed.

permazen/permazen,archiecobbs/jsimpledb,archiecobbs/jsimpledb,archiecobbs/jsimpledb,permazen/permazen,permazen/permazen