(manifest_test_get_query_language): Added
(manifest_test_run): Read and parse queries
(rasqal_cmdline_read_data_graph): Added from arg handling for graphs
(rasqal_cmdline_read_data_graph): Now handles stdin "-" from roqet.
Make utils use rasqal_cmdline_read_data_graph() shared code
Store background and named graphs in sequence

manifest_test gains a single raptor_sequence of rasqal_data_graph and
loses the 'data' and 'data_graph' fields.