Huge rewrite of the file loading/saving system. Normally safer in case of problem. Added incremental safety backups at regular intervals in the 'application data' directory (Windows) or $HOME/.grafx2 (unix). Keeps 8 files, saves every 30-60s and/or every 10-30 clicks.

git-svn-id: svn://pulkomandy.tk/GrafX2/trunk@1245 416bcca6-2ee7-4201-b75f-2eb2f807beb1

io.h

@@ -89,3 +89,8 @@ int  Directory_exists(char * directory);
 
 /// Scans a directory, calls Callback for each file in it,
 void For_each_file(const char * directory_name, void Callback(const char *));
+
+///
+/// Creates a fully qualified name from a directory and filename.
+/// The point is simply to insert a PATH_SEPARATOR when needed.
+void Get_full_filename(char * output_name, char * file_name, char * directory_name);