Removing @Consumes annotation b/c this endpoint doesn't actually consume any JSON.  This is causing a 415 error for the front end.
Merge pull request #143 from CruGlobal/bug/135

Bug/135
Admins can edit total amount due
 - feedback from conference admins is that frequently admins will need to change the total amount due for a registration for varying reasons.
 - caught a bug where total amount due would be wiped out by a subsequent update.
 - flow goes something like this now..
```java
if(updatedRegistration.completed() && !originalRegistration.completed()) {
	setCompletedTimestamp(currentTime);
}

//calculatedTotalDue derived from originalRegistration's completed timestamp and early registration factors
updatedRegistration.setTotalDue(calculatedTotalDue);

if(userIsAdmin) {
	updatedRegistration.setTotalDue(adminOverrideTotalDue);
}

registrationService.update(updatedRegistration);
```
I should check whether or not the logged in user has update rights on the conference, rather than admin rights on the registration.
 - Also, the logged in user should not be allowed to change their own amount due, for accountability
Fixing issues and comment from code review
Merge pull request #145 from CruGlobal/feat/edit-amount-due

Feat/edit amount due
Add an endpoint to retrieve all of the `Payment`s associated with a `Registration`
 - the service already existed on `PaymentService`, but there was no suitable endpoint

addressing issues from PR review
Merge pull request #146 from CruGlobal/feat/payments-for-registration

Get all payments for registration
Ensure registration cutoff date set before comparing against registration date.
Get current version of guava.
redegg has dependencies on current version.
Check for null registration entity when getting current registration with previous auth code.
Fixing bug where some registraiton updates would cause UnauthorizedExceptions - leading to a redirect loop

Fixing logic for calculating registration.totalDue
 - extracted business logic out into its own class for cleanness and eventual unit testing
Add an endpoint to get the permissions for the current user on a given conference
 - The service method already existed on `PermissionService`, but the end point had not yet been created
Changing equality.. how it was before would be quite non-functional
Adding functional tests for new permissions endpoint
Setting createdByUserId on a new registration view
 - Also, updating a registrationView shoudl only need READ conference rights, not ADMIN
Merge pull request #147 from CruGlobal/feat/132

Feat/132
Merge pull request #148 from CruGlobal/feat/134

Setting createdByUserId on a new registration view
Retire support of registration create on PUT

Change tests as per retiring of create registration on update.

Remove notion of current payment from registration.

Modify tests to recognize removal of current payment from registration
Merge pull request #149 from CruGlobal/retire-create-reg-on-put

Retire create registration on PUT