The Comment Blacklist is a means to moderate discussion. Contact forms are 1:1 discussion forums, ripe for abuse by users who have been removed from the public discussion, so we should respect any terms in the Comment Blacklist for contact form submissions.

At the very least, we should consider a contact-form-specific blacklist, if it isn't acceptable to use the Comment Blacklist.

Fixes #430

Changes proposed in this Pull Request:

• This change would check contact form submissions for terms in the Comment Blacklist before checking them with Akismet, treating contact form submissions more like how WordPress core treats comments.

Testing instructions:

Before applying this patch:

1. Add a term to the Comment Blacklist, like "bannedword".
2. Submit the contact form, using "bannedword" in any or all of the contact form fields.
3. Observe that the contact form submission succeeds.

After apply this patch:

1. Submit the contact form multiple times, with and without "bannedword" in all of the different contact form fields.
2. Observe that when "bannedword" is present, the contact form submission does not succeed, and when it is not present, the contact form submission succeeds.

Proposed changelog entry for your changes:

• The Comment Blacklist is now used to filter Contact Form submissions.