Add configuration for output size

Note that this has not been hooked up yet.
Make imports more consistent
Move worker to a package
Move worker limit to top

This makes it possible to control amount of maximum workers better.
Allow amount of instances to be controlled

Closes #13.
Execute workers at main

The idea is that separate parts of the application generate lists of
actions. These lists will then be combined and executed by the main loop
of the application. That way the limit set will work properly.