ApiListener bugfix

Found issue with ApiClientImplementation: FBReader sends intents with
extra string (see ApiServerImplementation) but API tries to get integer.
Event type in API changed to
String.
Revert "ApiListener bugfix"

This reverts commit 0ab9baddef3f6efd9a7d4e06bec432454df209f3.
ApiListener bugfix

Found issue with ApiClientImplementation: FBReader sends intents with
extra string but API tries to get integer. Event type in API changed to
String.