Made the `copy()` method public
Added `createOutputRepositoryManagerBuilder()` to make it possible to override the construction of output repos in sub classes
Added `createRepositoryManagerBuilderNoOut()` to be able to call the original code when overriding `createRepositoryManagerBuilder()`
Changed `ArtifactResult.toString()` to show the suffix
Fixed ceylon/ceylon-compiler#1764 Factor out the copying algorithm of the "copy" tool for re-use