Numerous fixes following the code review:

H1 title should be "Welcome to MailPoet version 3!", as per wireframes
remove logo in top right of the page
remove the classes feature-section one-col to the parent
new styles for #logger
progress bar: ensure that the color and size for the font are the same as our current progress bar.
display the progress bar at 100% when the import of subscribers and lists is complete
move loadSQL() function in tests/_support/Helper/Database.php
remove CSS browser prefixes
use AMD module definition to embed the JavaScript
remove extra whitespace in JavaScript file
remove the redundant functions descriptions
rename objectPlugin to mailpoet_mp2_migrator
replace private $chunks_size by the constant CHUNK_SIZE
add the constant IMPORT_TIMEOUT_IN_SECONDS
replace Helpers::mysqlDate() by $datetime->formatTime(time(), \MailPoet\WP\DateTime::DEFAULT_DATE_TIME_FORMAT)
make the log messages translatable
fix PHPDoc
replace Env::$plugin_name by 'mailpoet' in the translation functions
use $snake_case for variable names, use lowercaseCamelCase for method names, use CamelCase for class names
define MP2 table names as constants
add spaces around ternary operators
use the models for MP3 entities, instead of counting via raw SQL queries
use \ORM::for_table('some_table')::count()

webpack.config.js

@@ -247,7 +247,8 @@ config.push(_.extend({}, baseConfig, {
     ]
   },
   externals: {
-    'jquery': 'jQuery'
+    'jquery': 'jQuery',
+    'mailpoet': 'MailPoet'
   }
 }));