Using Zips.addEntries with FileSources that refer to directories results in exceptions

[lstreepy]

I was trying to use Zips to construct a zip file containing an arbitrary set of entries, using FileSource objects. However, if the FileSource refers to a directory, it results in a "Stream closed" exception:

	at java.io.BufferedInputStream.read(BufferedInputStream.java:345)
	at java.io.FilterInputStream.read(FilterInputStream.java:107)
	at org.zeroturnaround.zip.commons.IOUtils.copyLarge(IOUtils.java:322)
	at org.zeroturnaround.zip.commons.IOUtils.copyLarge(IOUtils.java:299)
	at org.zeroturnaround.zip.commons.IOUtils.copy(IOUtils.java:274)
	at org.zeroturnaround.zip.ZipEntryUtil.addEntry(ZipEntryUtil.java:131)
	at org.zeroturnaround.zip.ZipEntryUtil.copyEntry(ZipEntryUtil.java:115)
	at org.zeroturnaround.zip.Zips$CopyingCallback.process(Zips.java:655)
	at org.zeroturnaround.zip.ZipEntryOrInfoAdapter.process(ZipEntryOrInfoAdapter.java:26)
	at org.zeroturnaround.zip.Zips.iterateChangedAndAdded(Zips.java:569)
	... 4 more

I think the source of the bug is in this method: ZipEntryUtil#copyEntry(java.util.zip.ZipEntry, java.io.InputStream, java.util.zip.ZipOutputStream, boolean),
where on line 115 it does this: addEntry(copy, new BufferedInputStream(in), out)

Instead it should do this: addEntry(copy, in == null ? null : new BufferedInputStream(in), out) so the called method does not try to read from the input stream.