added O3 compiling flag

Makefile

@@ -1,4 +1,4 @@
-ARGS = -o fanorona -Wall -Wextra -pedantic -Werror
+ARGS = -o fanorona -Wall -Wextra -pedantic -Werror -O3
 SOURCE_CPP = source/Main.cpp source/Game.cpp source/String.cpp source/Vector.cpp source/Fields.cpp
 SOURCE_H = source/Game.h source/String.h source/Vector.h source/List.h source/Fields.h