Moves the alignments to the position specified by path. row_align
determines where the row is placed, and col_align determines where column
is placed. Both are expected to be between 0.0 and 1.0. 0.0 means
left/top alignment, 1.0 means right/bottom alignment, 0.5 means center.
If use_align is FALSE, then the alignment arguments are ignored, and the
tree does the minimum amount of work to scroll the item onto the screen.
This means that the item will be scrolled to the edge closest to its
current position. If the item is currently visible on the screen, nothing
is done.
This funciton only works if the model is set, and path is a valid row on
the model. If the model changes before this icon view is realized, the
centered path will be modified to reflect this change.