Added testing env for PHP 5.4 and 5.5
Updated to Elastice v0.90.5.0
Refactored to meet new requirements of elastica lib
Added support for JsonSerializable
Fixed: replaced version by feature detection to determine if \JsonSerializer is supported.
Fixed typo in travis configuration prevented tests to be run in PHP version 5.5
Fixed typo in name of a constant
Fixed usage of incorrect method to determine the support of JsonSerializable
Merge pull request #7 from liip/elasticaUpdate

Elastica update