Minor fixes;

- Extract configuration to its own class.
- Handle StopIteration in Application to prevent it bubbling up too far; ultimately we probably want this to end the process.
-
Temporarily add Ruby-Prof.
miscellaneous stuff
Fix composition in SingleInterfaceApp.
Remove Vedeu.trace, tidy up :nocov:, move ruby-prof to test_helper.
Add arguments attribute to Command.
Add logs/ directory.
Merge pull request #30 from gavinlaking/twerks

Tweaks and twerks!