Add VALUES lexer token
Add RASQAL_GRAPH_PATTERN_OPERATOR_VALUES for SPARQL 1.1 VALUES
rasqal_graph_pattern_s gains bindings field

(rasqal_free_graph_pattern): Free new field if present.
(rasqal_new_values_graph_pattern): Added to make a VALUES GP
(rasqal_new_bindings_from_var_values): Added

Builds a bindings from a single variable and a sequence of values
each of which turns into a row of 1 value to match the SPARQL 1.1
short form
(rasqal_variable_write): Check args
(rasqal_variables_write): Added to write a vars sequence with commas
docs
rasqal_literal_print will print 'null'; so do not conditionally call it
docs
(rasqal_algebra_algebra_node_write_internal): Use rasqal_variables_write
(rasqal_new_select_graph_pattern): Add optional bindings arg
(rasqal_row_write): Added
(rasqal_bindings_write): Added
(rasqal_graph_pattern_write_internal): Write bindings
(rasqal_literal_print): Print NULL
(rasqal_row_print): Print "row:"...
Print "row:" in debug output and use rasqal_literal_print for nulls
Add parsing for SPARQL 1.1 VALUES block formats

Handles VALUE single var + values list; VALUES with list of vars and
large block.  On the outer GP it gets adds to the query, otherwise
gets added to the sub-SELECT GP, or as a VALUES GP.