auth - removed encryption, fixed display order

encryption should be handled by the framework (or at least the Auth provider) rather than  be manually performed by the user
admin.html - fixed verifyCredentials 

 $this->getModel()->loadBy('email',$email);
throws exception when the user isn't found (on the next page in the manual) 
Also the the auth provider should handle encryption (just as its parent) I beleive that the whole "verifyCredentials function isn't relevant as the Auth/Basic does it better.
admin.html added missing $this->
Merge pull request #67 from SimSimY/patch-2

Authentication & Encryption updates to the learn/app