Cache.fetchValueForKey -> Cache.fetch(key)
Cache.fetchValueForFetcher -> Cache.fetch(fetcher)
Cache.setValue -> Cache.set(value, key)
Cache.removeValue(_) -> Cache.remove(key)
Cache.removeAllValues() -> Cache.removeAll()
Update README with new Cache function names and expand some descriptions
doFailure -> fail, doSuccess -> succeed

See:
https://github.com/hpique/Articles/tree/master/Swift/Style%20guide%20for
%20functions%20with%20closure%20parameters
Minor fixes
Merge branch 'master' into feature/prettifying/swift-like-names
Merge pull request #91 from Haneke/feature/prettifying/swift-like-names

Swift-like names for Cache