Replaces busy workers with running tasks on wq-status.
Fixes typo on -W, and shows tasks running rather than worker state.
Code movement.

Remove unnecessary function declarations.
Localize long_opts structure to main.
Formatting.
getopt_long returns an int.
Improve signal handling.

Kill all children performing a service (GC tickets) or handling clients.  Have
select just sleep 5 milliseconds. Relying on SIGCHLD to break out select has
race condition problems (unless you use pselect which is not available
everywhere). This timeout is enough to prevent Chirp from dominating the CPU
while giving reasonably quick response time to these events: child death,
catalog advertisement, and ticket GC.
Localize some static variables into main.

Some formatting.
Minor logic changes.
incompatible -b/-e option check.
Make arguments consistent.
Factoring: Split get_output_file() from get_output_files().
Factored time and performance out of file types.
Factored common message pattern into recv_worker_msg_retry.
Factored generation of cached name to a single location outside of get_output_item.
Factored do_thirput out of get_output_file().
Factored get_file from get_file_or_directory.
Explanation of why HDFS can't do quotas.
Remove old comment.
Only decode/collapse paths.

This operation cannot fail.
Move cfs global.
Move path resolution to CFS layer.

The Chirp server now only URL decodes and collapses paths from the wire. The
CFS layer now resolves these paths which usually involves prepending the root
path and a final collapse.

The net result of this change is reduced coupling of modules. Now every module
"above" the CFS layer sees the same abstraction of the Chirp root as clients.