add standard capture controller.
fix 5.3 compatibility.
[travis] configure composer to prefer source
fix compatibility with 5.3
[doc] add doc to basic setup on how to confiure capture controller.
[doc] replace instruction with PaymentDetails.
[doc] fix note block style
[doc]replace contextName word usages with paymentName.
[doc] add not to configure capture controller.
[doc] update examples with capture controller from bundle.
[doc] remove outdated code from omnipay example.
Merge pull request #20 from Payum/capture-controller

Add standard capture controller.