Remove broken code references to ManageWP Worker

This plugin is incompatible with ManageWP Worker plugin because it redefines $mmb_core in init.php:1807 and MMB_WORKER_VERSION in helper.class.php:20.

I noticed in file headers that this plugin is mostly a copy of ManageWP Worker, but the copied code makes the two plugins incompatible. Please remove the code references mentioned above, since they serve no other purpose but to break ManageWP Worker.

https://ww.wp.xz.cn/plugins/iwp-client/