* Make tests work after the changes introduced in #3793

* Remove unneccessary import

* Make StorageProofChecker happy

* Update some tests

* Check given validator set against set found in storage

* Use Finality Grandpa's Authority Id and Weight

* Add better error handling

* Use error type from decl_error! macro

* Create module for checking ancestry proofs

* Use Vec of Headers instead of a HashMap

* Move the ancestry verification into the lib.rs file

* Change the proof format to exclude `child` and `ancestor` headers

* Add a testing function for building header chains

* Rename AncestorNotFound error to InvalidAncestryProof

* Use ancestor hash instead of header when verifying ancestry

* Clean up some stuff missed in the merge

* Move `bridge` crate into `frame` folder

* Make `bridge` pallet compile after `the-big-reorg`

* Update decl_error usage

* WIP: Update error handling to use DispatchResult

* Get module compiling with new error handling

* Make tests compile again

Main change was updating the usage of InMemoryBackend

* Move `sp-state-machine` into dev-dependencies

* Bump dependencies to v2.0.0

* Remove some stray comments

* Appy code review suggestion