(gdb-read-memory-custom)

(gdb-read-memory-custom)
(gdb-memory-set-address, def-gdb-set-positive-number)
(def-gdb-memory-format, def-gdb-memory-unit): Update memory buffer
after changing settings.
(gdb-invalidate-disassembly): Update when first shown.
(gdb-edit-locals-value): Fixed.
(gdb-registers-handler-custom): Print registers in right order and
allow changing register values (only for current thread yet).