Make pack reader agnostic about naming scheme

Instead of enforcing that pack files must be named according to a numeric
sequence, just scan the directory and look for files whose names end with
".pack".

Signed-off-by: Morten Hustveit <morten.hustveit@gmail.com>
Document the ROOT command line argument

The first non-option argument to ca-cas and ca-cas-repack signifies the root
directory for storage, and was previously undocumented.

Signed-off-by: Morten Hustveit <morten.hustveit@gmail.com>
Support writing empty objects to pack files

The test for short writes accidentally also tested for empty objects.

Signed-off-by: Morten Hustveit <morten.hustveit@gmail.com>
Write temporary pack files to pack subdirectory

This enables having pack files on a separate file system.

Signed-off-by: Morten Hustveit <morten.hustveit@gmail.com>
Merge u02:/usr/src/cantera-cas
Add support for the LIST command

The code added to support this feature is meant to useful for implementing
garbage collection and global repacks.

Signed-off-by: Morten Hustveit <morten.hustveit@gmail.com>