Task does not continue on failure with --force because done() is not called

[craig0990]

The tasks/jsdoc-plugin.js file is missing a call to done() after line 117. This causes Grunt to hang indefinitely when JSDoc exits with a non-zero error code, even when using --force.

(We are slowly migrating to JSDoc and want to generate whatever JSDoc can handle at the moment, hence the use of --force)

I'll submit a pull request shortly.