This significantly reduces the dependency closure of ethclient, which no
longer depends on core/vm as of this change.
All uses of vm.Logs are replaced by []*types.Log. NewLog is gone too,
the constructor simply returned a literal.
* build: modify the iOS namespace to iGeth (gomobile limitation)
* mobile: assign names to return types for ObjC wrapper
* mobile: use more expanded names for iOS/Swift API