Add CreateEventEx, OpenEvent, ResetEvent and PulseEvent.

Also change eventAttrs to use the local definition of the
SecurityAttributes type, not the one from syscall.

GetConsoleScreenBufferInfo is also changed by re-running 'go generate'
to pass a pointer to ConsoleScreenBufferInfo (instead of a pointer to
pointer).

Change-Id: I08dff4360186b04c55fd0362e31920f38206157b
Reviewed-on: https://go-review.googlesource.com/56110Reviewed-by: Alex Brainman <alex.brainman@gmail.com>
Run-TryBot: Alex Brainman <alex.brainman@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>