updated for version 7.4.309
Problem:    When increasing the size of the lower window, the upper window
	    jumps back to the top. (Ron Aaron)
Solution:   Change setting the topline. (Nobuhiro Takasaki)
Added tag v7-4-309 for changeset 88a6e9f33822
updated for version 7.4.310
Problem:    getpos()/setpos() don't include curswant.
Solution:   Add a fifth number when getting/setting the cursor.
Added tag v7-4-310 for changeset ccac0aa34eea