comctl32: add ListView_SetCheckState and ListView_GetCheckState with tests(try3)

[Nikolay Sivov]

André Hentschel wrote:
> now using SNDMSGW
> ---
>  dlls/comctl32/listview.c       |    1 -
>  dlls/comctl32/tests/listview.c |    8 ++++++++
>  include/commctrl.h             |    6 ++++++
>  3 files changed, 14 insertions(+), 1 deletions(-)
I still don't follow you. How will it run on systems without unicode 
support?
In general it's better to correct all A-only macros to SNDMSG. This 
eliminates problem
with missed SendMessageW and superfluous AtoW conversion when it's present.

In native header ListView_SetCheckSate is implemented as a wrapper over
ListView_SetItemState which in turn is defined as SNDMSG.