fix: bug with conflicts

[okdistribute]

This is actually broken on the latest automerge (my fault: #1)

To reproduce:

0. Open two browsers
1. Add remote http://127.0.0.1:5000/groceries
2. Add some items to todo list on both sides
3. Hit 'push' on one side
4. Hit 'fetch' on the other

new.js:1536 Uncaught (in promise) RangeError: Expected seq 3, got seq 2 from actor 0000
    at applyChanges (new.js:1536)
    at BackendDoc.applyChanges (new.js:1778)
    at Object.applyChanges (backend.js:29)
    at Object.applyChanges (automerge.js:93)
    at AutomergeTodos.<anonymous> (automerge_hooks.ts:85)
    at Generator.next (<anonymous>)
    at tslib.es6.js:74
    at new Promise (<anonymous>)
    at __awaiter (tslib.es6.js:70)
    at AutomergeTodos.applyChanges (automerge_hooks.ts:82)

New changes should fix this.

Also looking at making this part of the automerge library, this explains the issue: automerge/automerge#374