Adding Eclipse Configuration

I propose following change for better Eclipse Integration:

• Add code convention Eclipse Files in {project.directory}

  /conf/eclipse directory (java-code-stye-clean-up.xml and java-code-style-formatter.xml). These files are for andrus.

• Add automatically generated source folders (generated-sources/javacc/org/apache/cayenne/ejbql and generated-sources/jjtree) in Eclipse build path in cayenne-server module using the build-helper-maven-plugin plugin maven.