deps: upgrade zlib to 1.2.8
deps: fix zlib.gyp for zlib upgrade to 1.2.8

This adds new sources for gzip files and defines a new flag for mac and freebsd.
They are taken from third_party/zlib/zlib.gyp in Chromium repository.
doc: Update LICENSE for zlib 1.2.8
Merge remote-tracking branch 'upstream/v0.10' into v0.10