Removed Usage from not found during tc-pause

When there is no current task the usage was being displayed for the
tc-pause command. This has been fixed by simply removing the displayal
of usage. Although, since the pause function is only intended to really
work on the current task, perhaps the call to it with argc > 3 should
just be replaced by a usage display.
Display Usage when tc-pause given arguments.

If a task name is passed to the pause command, the usage is now
displayed. This is because the pause command really only acts on the
current task, so it doesn't make sense to have it operate on arbitrary
tasks.