Update jQuery for DNN 6

Change version of VS Docs file to 1.6.1
Remove jQuery script, it'll be included by DNN itself
Remove AJAX

Need to validate on server to support CAPTCHA
Clean up EmailService
Add CAPTCHA protection

By default, use a 3 second minimum & invisible textbox for protection; also provides intrusive "match the distorted code" protection, optionally.
Merge pull request #6 from bdukes/CAPTCHA

CAPTCHA