added Benchpress benchmarks

Makefile

@@ -9,7 +9,7 @@ all: json_unit
 
 # clean up
 clean:
-	rm -f json_unit
+	rm -f json_unit json_benchmarks
 
 # build unit tests
 json_unit: test/unit.cpp src/json.hpp test/catch.hpp
@@ -30,4 +30,9 @@ pretty:
 	   --indent-col1-comments --pad-oper --pad-header --align-pointer=type \
 	   --align-reference=type --add-brackets --convert-tabs --close-templates \
 	   --lineend=linux --preserve-date --suffix=none \
-	   src/json.hpp src/json.hpp.re2c test/unit.cpp
+	   src/json.hpp src/json.hpp.re2c test/unit.cpp benchmarks/benchmarks.cpp
+
+# benchmarks
+json_benchmarks: benchmarks/benchmarks.cpp benchmarks/benchpress.hpp benchmarks/cxxopts.hpp
+	$(CXX) -std=c++11 $(CXXFLAGS) -O3 -flto -I src -I benchmarks $< $(LDFLAGS) -o $@
+	./json_benchmarks