Better way to get Causal links.

[masri321]

Currently the api call to get the causal links is relatively slow because it uses brute force to search for episodes that contain timeouts, then searches for their callbacks. The same method is also used for XHR events. A better method would greatly speed up the load time for the visualization. This method is called "episodesContainTimeouts" and is located in src/main/java/com/clematis/core/episode/episodeResource.java