allow to change local files

- fuse/filecache:
     * add filecache_upload_patch
     * allow opening files in modes other than RDONLY
 - fuse/hashtbl:
     * add folder_tree_upload_patch
 - fuse/operations:
     * allow opening files in modes other than RDONLY
     * add members to private context which allow tracking of
       not-yet-uploaded files and files opened for writing and
       files opened in read-only mode
 - mfapi/apicalls/upload_patch:
     * supply x-filename and x-filesize headers
 - mfapi/apicalls/upload_simple:
     * do not supply the x-filehash header as it is not used by the
       server
 - utils/hash:
     * hex characters must be lower case for the server
 - utils/strings:
     * clean up unused functions strdup_join, strdup_substr,
       string_chomp
 - utils/stringv:
     * complete rewrite with different string vector implementation

fuse/hashtbl.h

@@ -23,6 +23,7 @@
 #include <stdio.h>
 #include <stdbool.h>
 #include <stdint.h>
+#include <sys/types.h>
 
 #include "../mfapi/mfconn.h"
 
@@ -72,8 +73,12 @@ bool            folder_tree_path_is_file(folder_tree * tree, mfconn * conn,
                                          const char *path);
 
 int             folder_tree_open_file(folder_tree * tree, mfconn * conn,
-                                      const char *path);
+                                      const char *path, mode_t mode,
+                                      bool update);
 
 int             folder_tree_tmp_open(folder_tree * tree);
 
+int             folder_tree_upload_patch(folder_tree * tree, mfconn * conn,
+                                         const char *path);
+
 #endif