Use DestroyIcon for releasing the resources associated with created icons.

(Reported by David Saez Padros.)

For pipes/char devices, st_dev and st_rdev should be the fd, st_nlink
is always 1, and st_mode is S_IFIFO and S_IFCHR respectively.
Added tests to prove the new behaviour right.

kernel32: Fix the GetComputerName* functions to not write to the buffer at all if there is not enough space.

Add tests for the GetComputerName* functions that show this issue.

Fix an off-by-one error in setting the size when there is not enough space.

Remove the exception handlers for GetComputerNameW,
GetComputerNameExA/W, since testing on XP SP2 shows that access
violations are not caught and these are not present on Win9x, which
does have an exception handler.

Show that context changes in vectored handler also affect stack handlers.
Show that vectored handlers also get the changed context.Eip value.

instead of painting over the desktop.

token impersonation levels it accepts and to show that it doesn't
accept primary tokens.