Added relation between expense and category.
Fixed test class name
setCategory in expense service
addExpense renamed to create and returns the newly created expense
Added findAll method to category service
Added ability to create an entity model without a backing entity
Can now specify category when adding new expenses
Will now only load entity once if its backing a null entity.
Will only attempt to load if there is an identifier.
Added missing transactional annotation to set category
Verify date is not null when creating expenses
Verify description is not null when creating expenses
Verify description is not empty when creating expenses
Verify cost is > 0 when creating expenses
Added missing spring bean in test
Added missing bootstrap.js
Styling of add expense panel
Added id attribute to bootstrap javascript tag to prevent it from being contributed to the header once by components and bugging everything out with two javascripts fighting for control.
Use wicket-bootstrap to add all resources in the base page instead of adding it manually.
Updated wicket test to use a <div> tag for components when calling startComponentInPage(Class)
Changed add expense panel into a modal dialog