[OGR/WFS] Change required to iteminfo for OGR and WFS

[dmorissette]

Need to make the change described below for OGR and WFS connections.  Be 
careful, WFS connections are a wrapper around OGR connections.

Steve Lime wrote:
> 
> Hi Folks: In order to get dynamic joins working for query and
> classification I need to request that developers make a modification to
> the routines that muck with the void *iteminfo layer variable.
> Previously it was assumed that the contents of the layer->items variable
> were items related only to the core data (i.e. a single shapefile or SDE
> query). With joins that's not the case. The items could come from the
> core data OR from a dynamic join. (I'm planning on DBF and MySQL support
> for the 3.7 release) So, the vendor specific code needs to be altered to
> take this into account. For example, for shapefiles iteminfo really is
> just a list of DBF item indexes for the items we need. I will change
> that so iteminfo is a pointer to a struct that contains an array of
> indexes plus the length of that array since we can't assume it's the
> same length as the layer->items array. I'll take care of the shapefile
> and SDE modifications, but will need help for the others. Clear as mud?
> Contact me with questions...
> 
> Steve
>