* Remove Travis CI

* Implement ssz merkle root function

* Implement object hash function

* Add a hash-derive implementation

* Implement spec_hash for Vec

* Move type parameter to fn

* Integrate ssz_hash into runtime

Thanks Paul!

The former claimed to have built on blake2-rfc, so I assume it's newer, and it indeed has a nicer interface.

Lighthouse's ssz depends on `ethereum-types`, while we need to use `substrate_primitives`, so we can't yet directly
reference it on `crates.io`.