Unwraps default 'target' attribute.

Fixes bug introduced by 95732a2df83a62da47e7dd9c8dfb2f8c906a7781, discussed in #64 - a `target` option was added as a jQuery-wrapped element selection, but the code tries to use `target` as a raw string. This breaks the code that appends the notification to the container, causing the notifications to not display at all.