adding first solr integration as part of issue #9

This PR requires a local installation of Solr using the schema provided in the `src/test/resources/index/schema.xml` file. The connection details are kept in `src/main/resources/mamute.properties` file. First step towards #9 
DatabaseTestCase has some static resources because we didn't want to set up the same resources for each child of that class. I believe is ok to do everything on `@Before setup` and remove statics for now, let me know if you see any problems with it!