Add command list to -h output

Addresses #15

listener.c

@@ -479,6 +479,16 @@ static struct watchman_command_handler_def commands[] = {
   { NULL, NULL }
 };
 
+void print_command_list_for_help(FILE *where)
+{
+  int i;
+
+  fprintf(where, "\n\nAvailable commands:\n\n");
+  for (i = 0; commands[i].name; i++) {
+    fprintf(where, "      %s\n", commands[i].name);
+  }
+}
+
 void register_commands(struct watchman_command_handler_def *defs)
 {
   int i;
@@ -896,4 +906,3 @@ bool w_start_listener(const char *path)
 
 /* vim:ts=2:sw=2:et:
  */
-

opt.c

@@ -75,10 +75,14 @@ void usage(struct watchman_getopt *opts, FILE *where)
     fprintf(where, "\n");
   }
 
+  print_command_list_for_help(where);
+
   fprintf(where,
 "\n"
+"See https://github.com/facebook/watchman#watchman for more help\n"
+"\n"
 "Watchman, by Wez Furlong.\n"
-"Copyright 2012-2013 Facebook, Inc.\n"
+"Copyright 2012-2014 Facebook, Inc.\n"
   );
 
   exit(1);
@@ -249,4 +253,3 @@ bool w_getopt(struct watchman_getopt *opts, int *argcp, char ***argvp,
 
 /* vim:ts=2:sw=2:et:
  */
-

watchman.h

@@ -713,6 +713,7 @@ struct watchman_getopt {
 bool w_getopt(struct watchman_getopt *opts, int *argcp, char ***argvp,
     char ***daemon_argv);
 void usage(struct watchman_getopt *opts, FILE *where);
+void print_command_list_for_help(FILE *where);
 
 struct w_clockspec *w_clockspec_new_clock(uint32_t root_number, uint32_t ticks);
 struct w_clockspec *w_clockspec_parse(json_t *value);
@@ -757,4 +758,3 @@ struct watchman_client_subscription {
 
 /* vim:ts=2:sw=2:et:
  */
-