Review grid system strategy for mnemonic display

[ilanolkies]

      {rows.map((row, i) => {
        const columnWordIndex = [row, row + rows.length, row + rows.length * 2]
        return (
          <View style={grid.row}>

This will prevent rewriting word index calculation, then use columnWordIndex[0], columnWordIndex[1] and columnWordIndex[2]

Originally posted by @ilanolkies in #162 (comment)

[jessgusclark]

Also adding that the textfields need to have an order where the user can click "next" on their keyboard and it will take them to the next numbered item.