Update TreeList.h
Added vertical images to replace 2 horiz

Added vertical images to replace 2 horizontal images (silktree,
silkTree_winter_vertical.jpg and white oak,
whiteOak_winter_vertical.jpg) which would not fit properly into search
drop-down
Updated media to reference new vertical images
Put back in one horiz image ref
Updated DB, populated species table, vert. images
Changed vert images back to horiz
Merge branch 'ui' of https://github.com/asb-school/AU-Arboretum-Prototype-2
Added search controller, setup notification center for adding observer to select trees