bugifx: remove 'static' attirubte from global enum
workaround for util::stringify does not exist
add src/parser.cpp to make-all command
add parser#symbol_
add parser#tag
complete refactoring parser.cpp
use number::value instead of dynamic_pointer_cast and old-style cast
remove obsolete declarations in util.h
add compat definition for std::make_unique in util.h
include util.h from parser.cpp
initialize nil::_instance at the very beginning time
add missing object data accessors
add util::stringify
link main.cpp and util.cpp