Fix dependencies

Unittest is not required to use this, just to test it.
First pass at implementing 'cp'
Fix import for builder.dart test
Merge branch 'develop' into feature/cp
Incomplete system tests

Create and manipulate stuff in /tmp/ so inherently linux only.
Remove silly macro

Bonus points if you understand it
Further work on the system tests
Fix ls for non directories
Tests almost completely working
More fixes for system.dart
rm test now uses Completers

That way the actual bad code can be in the test and won't get run too
early.
Add return types to the tests
Correct return type of cp
Merge branch 'feature/cp' into develop

The link copy does not work, but cannot see why. Need to do other work,
so releasing with known issue.
Increase version
Merge branch 'release/0.0.2'