Use <lol/cli> and namespace lol::cli for argument parser API.

include/lol/getopt → include/lol/cli

@@ -16,3 +16,9 @@
 #include "3rdparty/clipp/include/clipp.h"
 #include "private/pop_macros.h"
 
+namespace lol
+{
+
+namespace cli = clipp;
+
+};