filename is read from and written to this buffer instead of using the get/set
methods of the given parameter (now used by win32ParamDialog() and similar
dialogs using the "Browse" button)
- added file extension support for bx_param_filname_c
- fixed showing of tab control child lists
- added special disk menu for the win32 ParamDialog
- on win32 use the ParamDialog instead of textconfig submenus (TODO: gui dialog
replacement for the start menus
- implemented dependency handling for boolean items
- now show all items if not at runtime
- moved init code for checkbox and combobox controls to their create functions
- TODO: handle child lists, dependency handling for enum items, several options
of the parameter types
* ported the basic functionality of the wx ParamDialog to win32
* moved AskFilename() function to the new file
* win32ParamDialog() now used for the external USB hub (if present)
* TODO: with some extensions it might be possible to use it for all runtime
dialogs and to implement a gui replacement for the textconfig start menu
