v0.4.0

Apollo Android v0.4.0

Fix stackoverflow crash in clearing normalized cache, make clear httpcache public (#563)
Handle list with null items (#567)
Add invalidate cached item by key from Apollo store (#568)
Change CacheControl to Interceptor based Fetcher (#556)
Generate operation id and add option to send to server instead of document (#569)
Introduce Apollo Store Operation (#573)
Input field marshaller (#576)
Replace Moshi with generated marshaller for operation json serialization (#578)
Fix issue with serializing list of objects (#580)
Remove Moshi from cache layer (#582)
Builder improvements proposal (#421)
Model ApolloCall/Query/Fetcher state as FSM (#577)
Fix issue with ArrayIndexOutOfBoundsException for list items with null (#586)
Second attempt to fix ArrayIndexOutOfBoundException (#587)