Initial user registration stuff: (refs #113)

* Stored procedures (`stored_procedures.sql`)
* Database connectivity (`UserDbProvider.cs`)
* Input validation (`UserRegistrationValidator.cs`)
* Registration service endpoint (`UserRegistrationService.cs`)
* Registration page (`UserRegisterResponse.cshtml`)
Removed old TODOs, updated product unit tests
Refactored, moved stuff around, extracted types into own files, reformatted code
Preprocessor check for debug mode
Load local copy of jQuery if it fails to load from the CDN
User registration validation
Fixup jQuery commit
Fixed exceptions being thrown on null address values
Encrypt password when creating new user
User registration complete! (closes #113)