Add static method in State to get it by name

[Suvitruf]

Hi.
When I use this lib, I need to compare result of HealthClient.getHealthyServiceInstances and HealthClient.getAllServiceInstances with State.

But in HealthCheck class status represents as string. So, mb it's not bad idea to make method for getting State by it's name like c6b022f ?

[rickfast]

sounds good. make a pull request with the change and I'll merge it. thanks!

[Suvitruf]

Ok. Did it #25
But this pull request has to many useless commits also, cause of merge with original repo =/

[rickfast]

See 0dea4d0