per-step jobconf in local mode

Gave the local and inline runners some much-needed TLC.

They now:
 * support jobconf defined on a per-step basis
 * respect `mapred.map.tasks` and `mapred.reduce.tasks` set on a per-step basis
 * run each step in its own working directory

In addition, inline mode now runs tasks in the working directory and supports `upload_files` and `upload_archives` (it doesn't support setup because it doesn't use subprocesses).

Also fixed an off-by-one error in inline mode counter parsing.