i2ptunnel: Fix gzip footer check in GunzipOutputStream (Gitlab #458)
- verifyFooter() was never called due to incorrect footer length check
- footerSize calculation was incorrect (off by one)
- footer buffer rotation was incorrect
- CRC32 was not computed
All bugs present since original checkin, 2015-05
Additional cleanups:
- remove write(byte[]) method present in super
- toString() improvements to aid debugging = do not reset inflater when finished so toString() data remain valid
Closes #458 (closed)