ZipHandle: remove unnecessary entryCount logic
ZipEntry: fix whitespace
fixup! ZipHandle: remove unnecessary entryCount logic
ZipHandle: consolidate setFile methods

This eliminates duplicate code between the two setFile methods, in favor
of having one delegate to the other.
ZipHandle: make length computation more efficient

The previous approach was to skip one byte at a time over the entire zip
entry, which was excruciatingly slow. The new approach simply asks the
ZipEntry for its uncompressed size directly.
Merge branch 'zip-performance'

This branch greatly improves the performance of ome.scifio.io.ZipHandle,
as well as providing some miscellaneous code cleanup of that class.