added sqlite query result and enhanced column generator and value extractor

src/sql/value_extractor.cpp

@@ -0,0 +1,29 @@
+#include "matador/sql/value_extractor.hpp"
+
+namespace matador::sql {
+
+value_extractor::value_extractor(std::vector<any_type> &values)
+: values_(values)
+{}
+
+void value_extractor::on_primary_key(const char *, std::string &pk, size_t)
+{
+  append(pk);
+}
+
+void value_extractor::on_revision(const char *, unsigned long long int &rev)
+{
+  append(rev);
+}
+
+void value_extractor::on_attribute(const char *, char *x, const utils::field_attributes &)
+{
+  append(x);
+}
+
+void value_extractor::on_attribute(const char *, std::string &x, const utils::field_attributes &)
+{
+  append(x);
+}
+
+}