* crypto.spec: make `keyResponder` a local var
it is never used between functions, so making it external was confusing
* Persist encryption state to the rust room list.
* `MatrixClient.shouldEncryptEventForRoom`: fix for rust crypto
Previously, we were not bothering to ask the Rust Crypto stack if it thought we
should be encrypting for a given room. This adds a new method to `CryptoApi`,
wires it up for legacy and Rust crypto, and calls it.
* Tests for persistent room list
Richard van der Hoff
11348f9532