Work queue test improvements

After playing with the work queue test i found some issues that i thought were worth fixing.

The first issue is a test failure when the number of items to sent is lower than the number of inflight items. The logic within the program raises the number of items to sent to the number of inflight items. This leads to a mismatch between the specified number of items to sent and the actual number of items sent.

The second issue is 4 space indentation in the help message. After some quick research i found that gcc, make, sed and [http://docopt.org/] use 2 space indentation.

The third issue is missing options (help and verbosity) in the help message.