(FR #619) Document db_switcher
Added support for simplification of CiviCRM API results. There is a bug in the Contribution API that is handled by a work-around for the time being
Adding configuration option for a path to a checkout of DonationInterface (or at least a sparse checkout with the i18n files).
A better translation for the Italian thank you emails.
A complete rewrite of the Thank You module using Twig for templating and a reworking of i18n.

I would recommend reviewing the updated code as a whole and not simply looking at diffs.
FU r2131

Fixed a static path, and made the unsubscribe link use 'h=' instead of 'hash='
Don't htmlescape watchdog
distinguish recurring vs queue consumer errors, lie less
honor --batch argument to drush
Restoring previous behavior and only ACK'ing on explicit success. FU r2003.

N.B. - It is very common to get the payment details from PayPal before we get the new subscription message.
Adding support for simple fallback languages
Adding script to make thank you messages
Using the function and its fallbacks instead of reinventing the wheel.
Adding all languages that are already deployed from 2011.
A nice litte note on top, FU r2176
Stupid tabs. FU r2179
A little less verbose for normal operation of the TY email and print_r'ing a few arrays.
Forcing Twig to not escape the unsubscribe URL
fu r2167 WOW that was crazy.
(fu r2168) failmail subject line specifies which module produced an error