Added limit posts by post type

[mgratch]

No description provided.

[kjbenk]

Thanks for the contribution :) I will have a look at the code to see if everything works ok and then I will merge commit the pull request.

[kjbenk]

I would remove this line since the Limit by Post Type option should be independent from the Limit by User

[kjbenk]

This feature enhancement seems to only check if the current post is of a certain post type before a user tries to publish the post. Was this the intention of this feature, or did you want a certain user to be limited in number to the amount of posts they can publish of a certain post type?

[mgratch]

I wrote the code to limit post type creation gracefully for all users, I really like your approach.

But I agree that for it to be ready to push to the repository it should also allow limitation of post type creation by users and caps.

[kjbenk]

To really make this feature great I think we will need to add this functionality:

1. Admin can select which users are limited by their roles or capabilities
2. Admin can select which post types are limited on a per user basis
3. Limiting by Post Type and Limiting by User role and capabilities are both exclusive to each other in saving the settings, but they build off each other determining if the user is able to publish another post or not

Once you have built in this functionality I will be happy to merge :)