tyrone-wu 02d1db5fc0 aya: remove unwrap and NonZero* in info
Addresses the feedback from :
- remove panic from `unwrap` and `expect`
- Option<NonZero*> => Option<int> with `0` mapping to `None`

Refs: 
..
tests aya: remove unwrap and NonZero* in info
lib.rs aya,integration-test: improve integration tests for info API
tests.rs aya,integration-test: improve integration tests for info API
utils.rs aya,integration-test: improve integration tests for info API