Always give all the remaining space to the first wxTreeListCtrl column.

Always give all the remaining space to the first wxTreeListCtrl column.

Under GTK the columns of wxDataViewCtrl (and hence wxTreeListCtrl) are always
resized to cover the entire control width. For consistency, also do it under
the other platforms and give the remaining space to the first column and not
to the last one as GTK does by default, as the first column is more important.

Do this even if this results in reducing the size of the column: presumably,
if the entire control itself can be resized, the user wouldn't bother resizing
the columns and, on the contrary, if the user did resize the columns, the
entire control size is unlikely to change, so in practice we don't risk
overriding the user preferences and reducing as well as increasing the first
column width works much better by default as it doesn't leave the other
columns invisible after making the control wider and than reverting it back to
its initial, more narrow, state again.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@69182 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775