some expansions in quit(), mostly TODO notes to bring it up to standard

src/builtins/quit.pir

@@ -1,5 +1,18 @@
 .sub 'quit'
     .param int nargout
     .param int nargin
+    .param string mode :optional
+    .param int has_mode :opt_flag
+
+    if has_mode goto check_mode
+    goto finish_and_die
+
+  check_mode:
+    if mode == "force" goto just_die_already
+    # TODO: in finish.m, if we call "quit('cancel')" we should stop the exit
+    #       and continue execution from the point after this quit call
+  finish_and_die:
+    # TODO: Should look for and execute finish.m if it exists
+  just_die_already:
     die 5, 0
 .end