Please consider renaming collection artifact back to dexx-collections

[vlsi]

See relevant issue ben-manes/caffeine#364

The case is it often happens that people place artifact jars to a single folder, and they use just artifact name for the file name.

If different artifacts use collection for the artifactId, then it would cause trouble (like with com.github.ben-manes.caffeine:guava which happened to produce guava.jar :-/ )