* win32-nat.c (get_image_name): New function.

* win32-nat.c (get_image_name): New function.
(handle_load_dll): Use get_image_name function.
(get_child_debug_event): Avoid registering debug events until possibly execed
process is started.
(child_create_inferior): Allow invocation via shell so that command line
redirection, etc.  works ok.
(_initialize_inftarg): Add new command: "set shell" to control whether a shell
is used to start a process.