zlib optimizations for ARM
''by Adenilson Cavalcanti''

- zlib: where is it used?
    - Network operations (i.e. content-encoding: gzip)
    - PNG decoding
    - Android migration to Chromium's zlib (https://android.googlesource.com/platform/external/zlib)
- Decompression up to 120%, compression 10% - 36%