Added digester usage from utils
Removed m1 client support from DefaultProxyManager.java (m1 support should be done in another class, maybe LegacyProxyManager)
Removed unused classes: Checksum.java and DefaultRepositoryFileManager.java
Added unit tests for configuration package
git-svn-id: https://svn.apache.org/repos/asf/maven/repository-manager/trunk@374817 13f79535-47bb-0310-9956-ffa450edef68