reduce warnings when compiling tests, add constructor to base parameters, fixes gcc49 unit tests building

include/engine/api/base_parameters.hpp

@@ -69,6 +69,16 @@ struct BaseParameters
     // Adds hints to response which can be included in subsequent requests, see `hints` above.
     bool generate_hints = true;
 
+    BaseParameters(const std::vector<util::Coordinate> coordinates_ = {},
+                   const std::vector<boost::optional<Hint>> hints_ = {},
+                   std::vector<boost::optional<double>> radiuses_ = {},
+                   std::vector<boost::optional<Bearing>> bearings_ = {},
+                   bool generate_hints_ = true)
+        : coordinates(coordinates_), hints(hints_), radiuses(radiuses_), bearings(bearings_),
+          generate_hints(generate_hints_)
+    {
+    }
+
     // FIXME add validation for invalid bearing values
     bool IsValid() const
     {