xo-reader2 stack: expand symbol table to store typedefs

+ typedef utest
+ misc qol policy choices

src/reader2/DIfElseSsm.cpp

@@ -147,6 +147,7 @@ namespace xo {
             switch (tk.tk_type()) {
             case tokentype::tk_symbol:
             case tokentype::tk_def:
+            case tokentype::tk_deftype:
                 break;
             case tokentype::tk_if:
                 this->on_if_token(tk, p_psm);