Issue with update_tick in dc_core.js

## (!important) When a new tick is added to ohlcv and has the next interval, it's the open price should be the close price of the previous tick

in src/helpers/dc_core.js line 204

let nc = [t, tick, tick, tick, tick, volume] should be let nc = [t, last[4], tick, tick, tick, volume]
