(rasqal_new_bindings_from_var_values): Debug prints
(rasqal_graph_pattern_write_internal): Do writing here for bindings

Using rasqal_bindings_write() failed to do indenting.
(rasqal_bindings_get_row): Added to get a row from a binding
(rasqal_bindings_write): Removed
Added RASQAL_VAR_USE_MAP_OFFSET_VALUES and label for VALUES in SELECT
Allow rasqal_query_build_variables_sequence_use_map_row to bind VALUES

(rasqal_query_build_variables_sequence_use_map_row): Add bind arg to
allow forcing binding variables in a variables sequence.

(rasqal_query_build_variables_use_map): Process a query->bindings and
bind the variables seen

(rasqal_query_select_build_variables_use_map): Bind variables in a
sub-SELECT VALUES list
Add RASQAL_ALGEBRA_OPERATOR_VALUES for VALUES algebra node type
(rasqal_new_values_algebra_node): Added
Added bindings rowsource

(rasqal_new_bindings_rowsource): Added new constructor for a
rowsource over a rasqal_bindings
Convert values algebra node to a bindings rowsource

(rasqal_algebra_values_algebra_node_to_rowsource): Added

(rasqal_algebra_node_to_rowsource): Use above to do the conversion
Convert VALUES graph pattern to a bindings algebra node

(rasqal_algebra_bindings_to_algebra): Added to get the node from a
bindings

(rasqal_algebra_values_graph_pattern_to_algebra): Added to get the
node from a VALUES graph pattern

(rasqal_algebra_select_graph_pattern_to_algebra): Use
rasqal_algebra_bindings_to_algebra() to add a join above the final
sub-SELECT over the bindings algebra node