improve build process, part of #481

fix oneJar code coverage issue (coverage info corrupts JAR), test built SlamEngine JAR, allow environment variable overrides of backend-config, modify travis to use local mongodb override, auto-import zips data set when in travis builds. note: publish script has not been updated and jenkins is no longer expected to work.
Oh, and apparently you don't need to create the database, you can just use it. The build file passes locally with an un-authenticated MongoDB running at the default port.