manifest issues

br: 37548
Still not totally convinced that the line is not allowed to be 74 bytes long (including eol)
But the specs allow to cut off early, except for the name. So name is allowed to by 70 bytes
long, and only if the name is 70 or 69 bytes long the line will be 74 (73) bytes long. Else
it will be shorter than 72 bytes including eol.

git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@420641 13f79535-47bb-0310-9956-ffa450edef68

WHATSNEW

@@ -97,6 +97,9 @@ Changes that could break older environments:
 
 Fixed bugs:
 -----------
+* Manifests have improved line length handling, taking care of encoding.
+  Bug reports 37548 / 34425
+
 * <manifest> now closes the inputstream explicitly. Bug report 39628
 
 * <rpm> now also correctly searches the first element of the path. Bug report 39345.