v0.2.0

Changes:

• Library now requires at least PHP 5.5
• Add PHP 7 properly to build matrix and not allow it to fail, this means PHP 7 is now officially supported
• Add the WirecardHelper class to reduce boilerplate code when making requests
• Add MessageFactory to Context for ability to change Request/Response class
• Add some decoupling from Guzzle PSR7, this is still an ongoing effort
• Better examples in the documentation
• Fix bugs in Backend requests (thanks @WebentwicklerAt)

Experimental Changes (use with care):

• Implement all backend requests (untested as I lack a proper testing environment for these)