Updated to latest aether build
Disabled debug level for Apache HttpClient's wire logging
Updated transfer listener to properly deal with resumed downloads and existence checks
Decoupled from internal Aether util class (for the sake of licensing imported from https://github.com/sonatype/sonatype-aether/blob/aether-1.7/aether-impl/src/main/java/org/sonatype/aether/impl/internal/CacheUtils.java)
Emitted warnings for cyclic project dependencies