Added error returns for isAvailable and verify functions to allow callers to be able to go into different flows regarding touch ID unavalability.
Android:
Added option for user authentication required as some scenarios may not use it, defaults to true to keep compatibility with previous implementation.
Altered save so you can choose to save without fingerprint (same behavior as iOS).
isAvailable and verify functions return the same error codes as iOS to keep consistency for caller.
Added error returns for isAvailable and verify functions to allow callers to be able to go into different flows regarding touch ID unavalability.
Android: Added option for user authentication required as some scenarios may not use it, defaults to true to keep compatibility with previous implementation. Altered save so you can choose to save without fingerprint (same behavior as iOS). isAvailable and verify functions return the same error codes as iOS to keep consistency for caller.