Support for Symfony 4

Added

• Added support for Symfony 4
• Added service aliases for auto-wiring

Removed

• Removed support for PHP versions earlier than 5.6.

Documentation fixes

Documentation fixes

Improve documentation and add a useraction option

• Significantly improve documentation and host it at http://jmspaymentpaypalbundle.readthedocs.io (#79)
• Allow setting a useraction parameter in the redirect URL (#80) (docs)

Support for Symfony 3

1.1.0

Support for Symfony 3