Create distribution tasks for releasing the software

The project build currently mainly builds the Maven artifacts, but we also need to configure the different distributions we'd like to have. A copy from my mail to dev@...:

The release of Marmotta is a bit different from both, Jena and Stanbol:

• there is a common release number over all artifacts (different to Stanbol, easier maintenance)
• the primary means of release is the Maven repository
• there are two binary "launchers" we would like to release in addition: a .war file and a izPack installer that bundles also Tomcat
• there are a number of libraries that are worth releasing separately as libraries (Maven and download):

• ldclient as a Linked Data Client library
• ldcache as a Linked Data Caching library (builds on ldclient)
• ldpath as a RDF/Linked Data Query Language (builds on Jena or Sesame, can use ldcache)
• kiwi as a RDBMS-based Sesame backend with some advanced functionality (reasoning, versioning, transactions)

• there is a common source release consisting of the combined source code