Improve Java 8 configuration.
Upgrade dependencies.

Upgraded to Spring Boot 1.1.6, Spring Framework 4.1.0, Tomcat 8.0.12 and Lombok 1.14.6.
Improved PaymentProcessIntegrationTests to send Accept headers.

HTTP requests triggered in PaymentProcessIntegrationTests now set an Accept header of application/hal+json to make sure the content negotiation returns the correct media type.
Upgrade to Spring Data Evans release train.
Upgraded to latest Spring, Spring Boot, Tomcat and Spring Data Fowler snapshots.
Configured Travis to run on optimized build infrastructure.