Tab control update

[Robert Shearman]

Jon Griffiths wrote:

>Hi,
>
>A fairly large update to the tab control. This makes it work as per
>native in my app.
>
>Regards,
>Jon
>
>   +dlls/comctl32/tab.c dlls/comctl32/tests/tab.c
>    Items can be variable sized; use an accessor to retrieve them
>    Send WM_NOTIFYFORMAT/WM_QUERYUISTATE to match native messages
>

There is no point in sending WM_QUERYUISTATE. I believe it is only 
really used for the toolbar control, but the native comctl32 has a 
common framework that means it is sent for all controls.

>    Only create a scroll control when/if we need one (like native)
>    Dump tab extra data when tracing
>    Combine all Unicode/Ascii calls together
>    Pass infoPtr around instead of fetching it multiple times, store
>     hwnd and focus state in it too.
>    Calculate correct tab widths when TCS_FIXEDWIDTH is not given
>    Code simplifications/const correctness/formatting fixes
>    Add some new combinations to tests for correct tab sizes
>  
>

I haven't looked at the rest of the changes yet and I won't have a 
chance until Sunday, but the changelog looks sane enough.
Is it possible to split the patch up to make it more easily reviewable?

Rob