DL-176: Rename the DL artifact from com.twitter to org.apache.distributedlog
DL-176: Rename the DL artifact from com.twitter to org.apache.distributedlog

Author: Sijie Guo <sijieg@twitter.com>

Reviewers: Dave Rusek <drusek@apache.org>, Leigh Stewart <lstewart@apache.org>

Closes #102 from sijie/sijie/fix_pom_file_layout

sijie/bookkeeper,ivankelly/bookkeeper,ivankelly/bookkeeper,sijie/bookkeeper,apache/bookkeeper,sijie/bookkeeper,sijie/bookkeeper,sijie/bookkeeper,sijie/bookkeeper,sijie/bookkeeper,apache/bookkeeper,apache/bookkeeper,apache/bookkeeper,apache/bookkeeper,ivankelly/bookkeeper,sijie/bookkeeper,apache/bookkeeper