nautilus-grid-view.c: Change valign property of GridView
valign property of the widget responsible for the folder content was set to GTK_ALIGN_START. This widget was moved to the top part of the parent if this widget receives enough space. However, this is not needed in this situation, since GridView already placing folders and files from top to bottom. Also, the height of the GridView was bounded by parent height and by some linear function of the number of elements in a folder. Changing valign will force the GridView to fill all allowed vertical space.
Fixes #2301 (closed)