Issue #2817833 by Jo Fitzgerald, chiranjeeb2410, ckaotik, vaplas, svendecabooter, aleevas, bhanuprakashnani, heddn, quietone, mikeryan, alexpott, catch: Delay sql map table creation

This reverts commit dc222737.

Issue #2776975 by joelpittet, dawehner, tim.plunkett, xjm, pfrenssen: March 3, 2017: Convert core to array syntax coding standards for Drupal 8.3.x RC phase

Issue #2665992 by alexpott, klausi, heykarthikwithu, xjm, tstoeckler: @file is not required for classes, interfaces and traits

Issue #2676222 by alexpott, johnrosswvsu: Move MigrationInterface out of the migrate\Entity namspace now they are plugins

Issue #2613878 by edysmp, heddn, Adita, Lord_of_Codes, jian he, chx, miiimooo, alexpott, benjy, mikeryan: Use hash for Migration source keys, rather than verbatim values

Issue #2571499 by benjy, mikeryan, phenaproxima: idMap source and destination id filtering requires keys

Issue #2535458 by mikeryan, benjy, phenaproxima, EclipseGc, dawehner: Dispatch events at key points during migration

Issue #1392754 by tss, justAChris, jhodgdon: Comply with new documentation standards for @file for namespaced class files

Issue #2504417 by alexpott: Fix Drupal\Tests\migrate\Unit\MigrateSqlIdMapTest::testGetQualifiedMapTablePrefix()

Issue #2260121 by sun: PHPUnit Tests namespace of modules is ambiguous with regular runtime namespace (+ Simpletest tests).

Issue #697760 by sun: Replace getInfo() in tests with native phpDoc + annotations (following PHPUnit).

Issue #2213451 by andypost, bdone, benjy, penyaskito, chx, claudiu.cristea, damiankloip, gregboggs, InternetDevels, jessehs, jhedstrom, marvil07, mikeryan, pcambra, Xano, YesCT: Update Migrate API in core