add download link

git-svn-id: https://svn.code.sf.net/p/jackcess/code/jackcess/trunk@1362 f203690c-595d-4dc9-a70b-905162fa7fd2

README.txt

@@ -13,3 +13,5 @@ repository which is hosted on SourceForge:
 Homepage: https://jackcess.sourceforge.io/
 
 Project: https://sourceforge.net/projects/jackcess/
+
+Download: https://sourceforge.net/projects/jackcess/files/latest/download]