Modified the documentation.
Add the getIndexFields and getValidIndexFields methods.
Add getSolrSpecVersion method for the HttpServer and the controller.
Imeplement the getSolrVersion, getSchemaField and getValidSchemaFields for the EmbeddedSolrServer.
move SolrQueryResponseTransformer and SolrQueryReponseWriterFactory to the query package.
Remove the query(String query) methods from SolrQueryService.java.
Remove the depency on the d1_cn_index_processor.
Move the solr query part here since metacat-index needs to query the solr server too.