Add Java 8 to Travis CI build matrix
Merge pull request #6 from joschi/java8-travis

Add Java 8 to Travis CI build matrix
Merge pull request #7 from joschi/dependency-updates

Dependency updates
Merge pull request #8 from joschi/master

Fix JUnit imports in AttemptTimeLimiterTest
Implement FibonacciWaitStrategy

Similar to the ExponentialWaitStrategy the FibonacciWaitStrategy follows a
pattern of waiting an increasing amount of time after each failed attempt.

Instead of an exponential function it's (obiously) using a Fibonacci sequence
to calculate the wait time.

Depending on the problem at hand the FibonacciWaitStrategy might perform better
and lead to a better throughput than the ExponentialWaitStrategy.