Add support for NET+50 CPU and ModNET50 board

* Patch by Sam Song, 10 Feb 2004:
  Fix typos in cfi_flash.c

* Patch by Leon Kukovec, 10 Feb 2004
  Fixed long dir entry slot id calculation in get_vfatname

* Patch by Robin Gilks, 10 Feb 2004:
  add "itest" command (operators: -eq, -ne, -lt, -gt, -le, -ge, ==,
  !=, <>, <, >, <=, >=)