Config: Updated cache expiry period for static resources
Model: Updated constants per naming convention.
Service: Better use of Joda `Interval`s.
DAO: Updated `set()` method to prepare for
TimeSheetView.availableClients
Web: Made `TimeSheetController` endpoints more RESTful (like
`ContractController`).
Most of these server-side changes are related to the task 'Handy Admin
Links: Client page' (https://trello.com/c/8UfmSoql).
Moved function from view to model (getter only)
Updated validation error message.
In progress: Handy Admin Links: Client page (2/3,
https://trello.com/c/8UfmSoql).