Remove the usage of -O3 in CMakeLists.txt

refs #83
CMAKE_BUILD_TYPE variable should be used instead

CMakeLists.txt

@@ -16,7 +16,7 @@ catkin_package(
 	CATKIN_DEPENDS dr_eigen
 )
 
-set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -O3 -std=c++11 -Wall -Wextra")
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11 -Wall -Wextra")
 
 include_directories(
 	include/${PROJECT_NAME}