2.4.0
Added following API
Fetch variation name of campaign from test key
variationNameFor(testKey:)
Fetch variation info
boolFor(key:defaultValue:)
intFor(key:defaultValue:)
doubleFor(key:defaultValue:)
stringFor(key:defaultValue:)
objectFor(key:defaultValue:)
Deprecated API
variationFor(key:defaultValue:)