* Fix steps being mistaken for seconds
* Cap steps at `u32::max` seconds
* Fix overflow of steps in Rust
* Prevent overflow of `IntervalKind`
* Prevent overflow in `revlod/mod.rs`
Also replace some `as` with `from` and `try_from` as is recommended to
highlight potential issues.
* Ensure v2 doesn't store overflowing revlog ivls
* Lower steps cap in deck options
Whereas large card intervals are converted to days, revlog intervals use
i32s to store large numbers of seconds.
* Format
So, this is fun. Apparently "DeckId" is considered preferable to the
"DeckID" were were using until now, and the latest clippy will start
warning about it. We could of course disable the warning, but probably
better to bite the bullet and switch to the naming that's generally
considered best.
To coalesce successive note edits into a single undo op we'll need to
be able to get the original Undoable type, which is awkward to do with
a trait object.
