Introduce river mapfile generation (WARNING: Changes in config xml files required!). On startup the RiverMapfileGeneratorStarter is called by the server app. The starter invokes a call to RiverMapfileGenerator.generate() which reads all available rivers from the database and generates layers for each river (in theory...uncompleted) in a river.map file. The old MapfileGenerator which generates layers that have artifact dependencies is now in ArtifactMapfileGenerator.

<?xml version="1.0" encoding="UTF-8" ?>
<datacage>
    <user>SA</user>
    <password></password>
    <url>jdbc:h2:${artifacts.config.dir}/../datacagedb/datacage</url>
</datacage>