Automatically update DHT nodeslist

List is now automatically fetched from nodes.tox.chat and placed in the
user config directory. The list is updated once every 30 days, and
will attempt to detect problems and re-fetch the list if necessary.

Also fixed a couple file descriptor leaks and cleaned some things up.

src/configdir.h

@@ -34,8 +34,23 @@
 #define S_ISDIR(mode)  (((mode) & S_IFMT) == S_IFDIR)
 #endif
 
+/**
+ * @brief Get the user's config directory.
+ *
+ * This is without a trailing slash. Resulting string must be freed.
+ *
+ * @return The users config dir or NULL on error.
+ */
 char *get_user_config_dir(void);
+
+/* get the user's home directory. */
 void get_home_dir(char *home, int size);
+
+/* Creates the config and chatlog directories.
+ *
+ * Returns 0 on success.
+ * Returns -1 on failure.
+ */
 int create_user_config_dirs(char *path);
 
 #endif /* #define CONFIGDIR_H */