Added sign_up_enabled global variable

also fixed some indents + file location
Added check for sign_up_enabled. 

fix correct indents + fix file location. 
Added check for sign_up_enabled

Even though the sign-up form is not displayed when sign ups are disabled, we still need to refuse processing.
If signups are disabled do not display the form
Merge pull request #15 from iam1980/master

Added functionality to disable the sign up process.