* Rest Call (to be made by ajax) to retrieve data per currency code
* Added the d3 package (plotting currently against test data i.e.)
* DAO layer now does not return map but a list (sorting now done in service)
* USD mapped to EUR via d3 ajax call
* added all the exchange rates by selector..needs some styling
* updates are now done lazily as in acceptance criteria
* updating is now thread safe (only 1 thread enters to update)..if another thread enters after an update it will skip updating