1. Make sure that BLS -Verify APIs would only return `True` or `False` , no exceptions.
2. Use `eth2spec.utils.bls` instead of py_ecc for test generator
3. Add assertions in test generator
4. Add some special test cases for the -Verify APIs
5. Clean up the test format documents
* `block_header` operation to accept input of type `BeaconBlock`
* `voluntary_exit` operation to accept input of type
`SignedVoluntaryExit`.
* sanity/blocks to note that inputs are of type `SignedBeaconBlock`
protolambda
Danny Ryan
Hsiao-Wei Wang
Nathaniel Jensen