Add license

See merge request !15

[skip ci]

Update composer.json

See merge request !14

Fix hook for textdomain loading

See merge request !13

Fix hook for textdomain loading

See merge request !12

Fix i18n

See merge request !11

Bump WP compatibility

See merge request !10

Bump WP compat

See merge request !9

Bump WP compat

See merge request !8

Bump WP compatibility

See merge request !7

Bump WP compatibility

See merge request !6

Bump WP compatibility

See merge request !5

Remove rsync dependency

See merge request !4

Automated WP.org updates

See merge request !3

Introduce WP-CLI plugin scaffold bits

See merge request !2

PHP 7.3 compatibility

See merge request !1

Per https://make.wordpress.org/core/2015/07/02/deprecating-php4-style-constructors-in-wordpress-4-3/, WP 4.3 deprecates PHP4-style widget constructors, and their usage will trigger deprecated notices. Switching to PHP5 constructors is simple and resolves the problem.