Add rx support to hystrix-clj.

Add observe, observe-later, and observer-later-on functions to
hystrix-clj corresponding to observe(), toObservable() and
toObservable(Scheduler) methods added to Hystrix respectively.
Merge pull request #170 from daveray/hystrix-clj-observe

Add rx support to hystrix-clj.
[Gradle Release Plugin] - pre tag commit:  '1.3.1'.
[Gradle Release Plugin] - new version commit:  '1.3.2-SNAPSHOT'.
Version 1.3.1
Create CONTRIBUTING.md
Fix Exception vs Throwable typo

- This was using the Object overload rather than statically typed Func1<Throwable> method. This was caught when testing RxJava 0.11.0 which restores static type safety.
Merge pull request #173 from benjchristensen/fix-exception-throwable-typo

Fix Exception vs Throwable typo
[Gradle Release Plugin] - pre tag commit:  '1.3.2'.
[Gradle Release Plugin] - new version commit:  '1.3.3-SNAPSHOT'.
Version 1.3.2
Reference to Clojure Version
Reference to hystrix-event-stream-clj
RxJava 0.11.0
[Gradle Release Plugin] - pre tag commit:  '1.3.3'.
[Gradle Release Plugin] - new version commit:  '1.3.4-SNAPSHOT'.
Update Hystrix for breaking changes in RxJava 0.12

Basically throwing random "? super T"s all over the place and switching
from Func1 to OnSubscribeFunc. Tests pass. Please review for dumb
mistakes.
RxJava [0.11,0.12)

Trying to fix https://github.com/Netflix/Hystrix/issues/178

I tried this on local build, it worked. Trying now on build system.
[Gradle Release Plugin] - pre tag commit:  '1.3.4'.
[Gradle Release Plugin] - new version commit:  '1.3.5-SNAPSHOT'.