Sets the language and associates posts imported by WP ALL Import with WPML.
Currently, posts are only associated when they are in a secondary language.
For example, if your main language is French and your secondary language is
English, you must import your French posts first and your English posts
second, otherwise, the English posts won’t be linked with the French posts
(the language will be correctly set though).
This plugin assumes that your import file contains an attribute/column
specifying the language and an attribute/column with an identifier that is
common across all languages.