Add support for next_token to get_all_reservations, and have
get_only_instances use it to fetch all results.
add test that next_token is properly passed from get_all_reservations to
DescribeInstances call
Merge pull request #2189 from catlee/master

Add support for next_token to EC2 get_all_reservations. Fixes #2189.
Merge branch 'release-2.28.0'
Merge branch 'release-2.29.0'
Merge branch 'release-2.29.1'
Merge branch 'release-2.30.0'
Merge branch 'release-2.31.0'
Add release notes; bump to 2.31.1
Merge tag '2.31.1' into develop

Tagging 2.31.1 release.