changed a lot of details about checking history, this probably fucks everything up
removed debug logging
fixed next fetch time calculation
White space cleanup

Cleanup of whitespace before adding changes to the file.
Fetch candle history chronologically

By specifying $gt: -1 on the s (candle start minute) field the candle
documents will get fetched in chronological order. This means we can
skip one _.min, _.max check and the sortCandles function is rendered
obsolete.