Game can freeze due to error when rewinding time all the way

[1j01]

I'm not sure how to reproduce this exactly, but I've seen it crash the game loop when rewinding all the way. Obviously you need to drag some bricks around before rewinding to get this error:

Uncaught TypeError: brick.grabOffset is undefined
    updateDrag https://1j01.github.io/janitorial-android/src/game.js:3901
    render https://1j01.github.io/janitorial-android/src/game.js:5178
    animate https://1j01.github.io/janitorial-android/src/game.js:5561

Another error I got:

Uncaught TypeError: context.left is undefined
    nestedPatchFilter https://1j01.github.io/janitorial-android/lib/jsondiffpatch.umd.js:730
    process https://1j01.github.io/janitorial-android/lib/jsondiffpatch.umd.js:272
    process https://1j01.github.io/janitorial-android/lib/jsondiffpatch.umd.js:233
    patch https://1j01.github.io/janitorial-android/lib/jsondiffpatch.umd.js:3650
    unpatch https://1j01.github.io/janitorial-android/lib/jsondiffpatch.umd.js:3660
    handleRewind https://1j01.github.io/janitorial-android/src/game.js:4743
    animate https://1j01.github.io/janitorial-android/src/game.js:5535

I'm also seeing some general inconsistencies when rewinding, like bricks can end up floating in the air, as can Junkbot, who will then fall.