GA limits on downloads

[lcreid]

GA defaults to limiting queries to 1,000 returned results, and doesn't allow requesting more than 10,000 results in a query. Gaapi should make those limitations invisible to the end user.

[lcreid]

Gaapi has been modified to always return up to 10,000 rows, unless the user specifies a lower limit. It's still the user's responsibility to retrieve the additional rows using the nextPageToken.