emberjs/ember.js v2.12.0 on GitHub

#15000 / #15002 / #15006 / #15008 / #15009 / #15011 [PERF] Assorted performance improvements for modern browsers.
#14872 / #14871 / #14883 [PERF] Simplify action event handler.
#14360 [FEATURE factory-for] Implement factoryFor.
#14751 [DEPRECATION] Deprecate Ember.K.
#14756 [PERF] Disable costly eventManager support when unused.
#14794 [BUGFIX] Fix query param stickiness between models in ember-engines.
#14851 [PERF] only LOG_VIEW_LOOKUPS in debug
#14829 [PERF] only logLibraryVersions in debug mode
#14852 [PERF] only LOG_TRANSITIONS and LOG_TRANSITIONS_INTERNAL in debug
#14854 [PERF] only LOG_ACTIVE_GENERATION and LOG_RESOLVER in debug