Pulling Email From AD

Pulling a users email address from AD to add to their user account.
Requires the AppPool to run with an Identity that has a Domain account.
fixed so email is passed to the CreateUserParams method.
changed the place that the check for already saved user happens to no longer require user lookup and prevent deadlocked transactions.
fixed merge conflict from already saved users change.
added reference to System.DirectoryServices.AccountManagement.
used implicit typing to be consistent with module.
prevent null reference error when the user doesn't have an EmailAddress.
updated README to include pulling users email from active directory.
Merge branch 'feature/pulling-users-email-from-ad'