Brownju/bug/47

Added a module for validating user input, moved the location of orvsd_central.database.Model to orvsd_central.models.Model, and added tests to general.register() which the function itself still needs to be tested for correctness.
Because this has such little functionality, and does not seem to have any potential for expansion there is no reason for this to be a method. It's just extra code to sift through when working with the current codebase.