The blueprints/changes API is a bit different from the others, the total
that it includes is for each blueprint, not one total for all of them,
since there will be a different number of commits for each.
The function is passed the dict, and it can be used to select the total
to use for retrieving all of the results. If it isn't included it will
use data["total"] which works fine in most cases.
Add a limit argument to all potentially paginated results, equal to
whatever the composer backend is the total number of results. This still
has the potential to provide truncated data if the number of results
increases between the two HTTP requests.
Resolves: #404
