added Apache license file
added Apache license file

fhopf/solr-facet-example,boombastech/solr-facet-example,boombastech/solr-facet-example,fhopf/solr-facet-example,boombastech/solr-facet-example,fhopf/solr-facet-example,fhopf/solr-facet-example,boombastech/solr-facet-example