Support --recursive in the aws s3 ls command

This will just list the objects in the same order they come back
from s3, similar to `find . -type f` locally on a posix system.
Update test to not care about timezone info

Otherwise this will fail on machines not in my timezone.
Move param table population to S3SubCommand class

We don't need to go through the plugin/event system to
populate the argument table.  The S3SubCommand should own
and control the initial population of the table.

This also fixes a failing unittest.
Fix indentation and remove unnecessary code
Merge branch 's3-ls-recursive' into develop

* s3-ls-recursive:
  Fix indentation and remove unnecessary code
  Move param table population to S3SubCommand class
  Update test to not care about timezone info
  Support --recursive in the aws s3 ls command