Issue #1286298 by fietserwin, Triskelion, MegaChriz, charginghawk, osopolar: Don't create new items, only update existing

Issue #1953008 by MegaChriz, twistor, klausi: PHP Fatal error:  Nesting level too deep - recursive dependency? in FeedsProcessor.inc on line 199

Issue #2333029 by twistor, MegaChriz: Extend mapping API to allow for defaults and multiple callbacks

Issue #2339383 by mikran, MegaChriz, joelpittet: Items missing from feeds do not affect item hash even when action is taken based on that

Issue #1470530 by stefan.r, GaëlG, mikran, Cottser, gnucifer, MegaChriz, vinmassaro, kostajh, Mithrandir, riho, jaanhoinatski, nrambeck, byronveale, dbassendine, PsycleInteractive, imclean: Added Unpublish/Delete nodes not included in feed.

Issue #661606 by MegaChriz, twistor, Cottser, scottrigby, manojbisht_drupal, Mohammed J. Razem, agileadam, emilyf, tmsimont, bradjones1, hairqles, ldavisrobeson, selim13, a.ross, chromix, g089h515r806 | lunk_rat: Added Support unique targets in mappers.

Issue #2224643 by hanoii, MegaChriz: Added Support for input format configuration on a per-field basis .

Issue #1107522 by ditcheva, Uhkis, cthiebault, franz, nielsonm, Niklas Fiekas, twistor, mparker17, Lasac, guillaumev | jptl: Framework for expected behavior when importing empty/blank values + text field fix.

Issue #1166100 by twistor | Niklas Fiekas: Fixed Notices and warnings on mapping page, when no content type is selected for NodeProcessor.

Issue #1362378 by gordon, colan, Sutharsan, MegaChriz | mukesh.agarwal17: Added is_new addtribute to feeds_item.

Issue #1953008 by MegaChriz | carn1x: Fixed PHP Fatal error:  Nesting level too deep - recursive dependency? in FeedsProcessor.inc on line 199.

Issue #1848726 by ojohansson, twistor: Fixed Hash check fails when running multiple importers on cron.

Issue #1843146 by twistor: Add pluginType() method to be able to determine the plugin type without having to lookup the inheritance.

options.