Use Java 8 for the site.
Update Hystrix package info
Reduce the default Hystrix metric publishing to 2 seconds
Move to Java 8.

Closes #444.
Add a publisher for merging publishers into a single stream
Stream Hystrix thread pool metrics via SSE (#346)
Update example to Java 8.
Don't test this example for now.
Update release instructions with maintenance steps for example projects
Remove Java 7 from Travis build.
Wrap in Javadoc code block.
Try setting the max heap size for testing.
Serialize the tests on Snap CI too.
Timeout the Gradle daemon very quickly when testing.
Isolate the manual tests.
Timeout this daemon too.
Use a new classloader for each groovy snippet so the class is reclaimable.
Isolate the Hystrix tests as they bleed static state changes.
Run Gradle embedded.
Generate an aggregate test report.