* Including projects in Rate.history_for_user
* Moved the valid sort options to a constant on the RatesController
* Changed the ValidSortOptions to use the Project name for project_id
* Updated admin view to use RatesController::ValidSortOptions instead of a
duplicated string.
#1915
* Added SortHelper to RatesController
* Init and updating the sorting (pre 0.8 sort_update)
* RatesController#index will only render the layout on non-xhr requests
* Changed Rate.history_for_user to take an order clause
* Added rate_sort_header_tag and rate_sort_link to the SortHelper in order
to get the correct parameters for sorting Rates
* Added rate_sort_header_tags to the Rate lists
#1915
incorrect objects to Rate#for will now throw a Rate::InvalidParameterException
back to the caller.
Normally you don't need to be this strict but this is a public API that will
be consumed by several third parties so we need to be very clear what happened.
#1920
Eric Davis