## Proposed Changes
Change the canonical fork name for the merge to Bellatrix. Keep other merge naming the same to avoid churn.
I've also fixed and enabled the `fork` and `transition` tests for Bellatrix, and the v1.1.7 fork choice tests.
Additionally, the `BellatrixPreset` has been added with tests. It gets served via the `/config/spec` API endpoint along with the other presets.
## Proposed Changes
Implement the consensus changes necessary for the upcoming Altair hard fork.
## Additional Info
This is quite a heavy refactor, with pivotal types like the `BeaconState` and `BeaconBlock` changing from structs to enums. This ripples through the whole codebase with field accesses changing to methods, e.g. `state.slot` => `state.slot()`.
Co-authored-by: realbigsean <seananderson33@gmail.com>
