Added a Zend\Filter\Compress\Snappy to utilise php-snappy.
The php-extension provides a minimal API for google snappy (formerly Zippy). The snappy library itself is intended to provide fast, reasonable compressions and is widely available as libsnappy1 package.
Php-snappy is not hosted on pecl.php.net.
UnitTests supplied and passing. Code is PSR-2 compatible and closely matches other filter implementations.
#1 added snappy implementation
added compresssnappy to FilterPluginManager
fixed migration error: has no base class
unit test for Zend_Filter_Compress_Snappy, fixed code, enforced psr-2
removed unneeded blank line
Merge branch 'feature/filter-compress-snappy' into develop