Ensure new user is author of "registered" activity item.

Return the post ID created in wp_insert_user_activity().

When a new user is added manually by a site admin via wp-admin, ensure that the new user, not the currently logged-in user, is the author of the activity item.

After inserting the new activity item,  allow `wp_insert_user_activity()` to return the newly created activity item ID, so that other processing may take place like adding complicated post meta or taxonomy terms.

Props szepeviktor. Fixes #10.

Fix several i18n issues.

Fixes #11.

Prevents infinite loops when calling `wp_insert_posts()`.

Also bump to 1.1.0.

Sloppy backwards compat for my dumb architectural mistake.

* Move files around for better mu-plugins support
* Update readme's

Impersonates `wp-cron.php`. Fixes #1.

Prevents recursion, causing widgets not to save. See #5.

This can happen if a post is purposely inserted without an author, which causes the activity text to be incomplete.

This prevents incorrect "untitled" activity post title.

Also fix a bug that might cause empty plugin names.

Bump to 0.1.10.