HystrixAsyncCommand -> HystrixFutureCommand

As per https://github.com/Netflix/Hystrix/issues/321#issuecomment-57698763
FutureCommand.run() -> start()

Also getFallback() -> startFallback()

As per https://github.com/Netflix/Hystrix/issues/321#issuecomment-57700385
onFailureResumeWithFallback -> resumeWithFallback

As per https://github.com/Netflix/Hystrix/issues/321#issuecomment-57698845
HystrixExecutableInfo -> HystrixInvokableInfo

As per https://github.com/Netflix/Hystrix/issues/321#issuecomment-57702442
Race condition fixed: sometimes different thread pool is registered in HystrixThreadPoolMetrics and different one used for executing commands
Added 3 new constructors for common command setup
* These constructors specify some combination of HystrixThreadPoolKey and executionIsolationThreadTimeoutInMilliseconds
Reducing repetetive test code
Execution type is now correctly determined from method return type
Fixing a hystrix-examples compilation failure.

One of the examples still used the now-deprecated toBlockingObservable(). It now uses toBlocking() which allows one to actually compile the examples again.
Remove HystrixFutureCommand

Decided that we don't want to commit to this yet since it has an awkward interface until RxJava offers a scalar Observable solution.
Merge pull request #338 from benjchristensen/api-design

API Changes as per Design Review
Merge pull request #353 from kevinvandervlist/master

Fixing a hystrix-examples compilation failure.
Merge pull request #347 from sawano/master

Allow for @HystrixCommand to be used on parameterized return type
Merge pull request #343 from mattrjacobs/simplified-command-construction

Added 3 new constructors for common command setup
Merge pull request #340 from nurkiewicz/HystrixThreadPool-race-condition

Race condition when creating HystrixThreadPool