[WIP] Avoid creating unneeded hashes by using Hash#merge! instead of #merge.

The "row" hash created within each of these methods is modified and returned.
The intermediate hashes are unneeded since no one else can accidentally modify them.
I can't see the full context here, but since `row` is initially allocated a couple lines up, could we just do:

```ruby
row = {
  :col => cell_text,
  :id => whatever
  ...
}

row.merge!(drift_something)
```