Start new branch to get streak data, which is a JSON list of dates and
number of posts per day. This data can be fed into cal-heatmap.js and
display a calendar heatmap of post activity.

Switch fetcher library out to mkaz/fetcher lib which implemented GET
parameters and switches the way params are set, using url.Values instead
of a map of strings.
Update streak data to loop over posts based on date if number of posts exceeds limit of 100 returned per query