Inverted control flow, engine as library

luprex/core/Makefile

@@ -4,6 +4,8 @@ CXX=g++ -std=c++17 -Wall -g -Iinc -Icpp
 CPP_FILES=\
 	cpp/invocation.cpp\
 	cpp/spookyv2.cpp\
+	cpp/drivenengine.cpp\
+	cpp/driver.cpp\
 	cpp/util.cpp\
 	cpp/luastack.cpp\
 	cpp/traceback.cpp\