v0.3.0

Apollo Android v0.3.0

#368 Refactor package structure
#379 Introduce ApolloExceptions
#388 Java docs
#392 Flatten class generation
#396 Rename Cache to ApolloStore, CacheStore to Normalized cache; Add ability to clearAll from CacheStore
#405 Add Factory to create NormalizedCaches injected with Scalar adapters
#409 Extract Android specific stuff to separate module
#410 Add Java 8 Optional Api map, flatmap
#407 RxJava2 Module