Applied patch [ 607261 ] Fix: wxGrid: row and cell selection

Applied patch [ 607261 ] Fix: wxGrid: row and cell selection

This is a patch against version 1.222 of
src/generic/grid.cpp.

1. The patch contains a fix for the row selection as
mentioned by me on the wx-dev mailing list. After
selecting one row and deselecting it no new row
could be selected.
2. Another change has been made to the function
CoordToRowOrCol() and addresses an error mailed
to wx-dev by John Labensky. The error was that no
cell could be selected until a horizontal and vertical
resize of at least one cell has been made. The error
was that the function could not handle grids with
default row or columns sizes.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@17112 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775