Remove Debug Log Emit and Needless Success Message
Remove Usage Method
Add Target Command to Commands List

This makes for a better summary when running `xnt help`. Further, if someone
tries to run this as a command, it will result in the Command attempting to run
the ``default`` target
Fix variable name spelling mistake
Refactor build module loading

Add field to commands to flag the build module to be loaded. Refactor commands
to use dependency injection for the build module (this should allow for some
testing of the commands).
Rename runner back to xenant
Remove xenant tests

These will be replaced by tests on the individual commands
Replace newline character
Update Documentation regarding usage