Instead of setting up the default keys by building the key struct

directly with a helper function in the cmd_entry, include a table of
bind-key commands and pass them through the command parser and a
temporary cmd_q.

As well as being smaller, this will allow default bindings to be command
sequences which will probably be needed soon.

cmd-set-environment.c

@@ -34,7 +34,6 @@ const struct cmd_entry cmd_set_environment_entry = {
 	"grt:u", 1, 2,
 	"[-gru] " CMD_TARGET_SESSION_USAGE " name [value]",
 	0,
-	NULL,
 	cmd_set_environment_exec
 };