Break inclusion cycle: prototypes.h and commands.h included each

other.  Ensure headers in include/ can be included in any order
(except for econfig-spec.h, which is special).  New header types.h to
help avoid inclusion cycles.  Sort include directives.  Remove some
superflous includes.

src/lib/commands/info.c

@@ -37,18 +37,14 @@
 
 #include <config.h>
 
+#include <ctype.h>
 #include <errno.h>
-#include <string.h>
-#include <stdio.h>
 #include <sys/stat.h>
-#include <time.h>
 #if !defined(_WIN32)
 #include <dirent.h>
 #else
 #include <windows.h>
 #endif
-#include "misc.h"
-#include "player.h"
 #include "commands.h"
 #include "optlist.h"