Initial upgrade to Aspen 0.26

Some tests are failing.
Adapt tests to new unicode handling in Aspen

Aspen 0.26 introduced some additional strictness with regard to unicode.
This commit conforms our test suite to this new strictness.
Acknowledge researchers re: BEAST ticket #1460
Drop back to acknowledging reporters only
Merge pull request #1531 from gittip/BEAST-ack

Acknowledge researchers re: BEAST ticket #1460
Bump version to 10.1.25
Bump version to 10.1.25-dev
Merge pull request #1529 from gittip/aspen-0.26

upgrade to Aspen 0.26
Bump version to 10.1.26
Bump version to 10.1.26-dev
Merge branch 'master' into elsewhere