added unit test for reverse-sorting transaction items
changed default scope for transactions to sort by reverse chronological order
removed unnecessary line of code
adjusted features for new sort order
added TransactionItemPresenter
use TransactionItemsPresenter in TransactionItemsController and related views
misc corrections to features related to re-ordering transaction items
moved new transaction form to the top of the list
alphabetized extensions
correcting insertion logic for new transaction items
added find method to array extensions and used it in NewTransactionItemViewModel
reverted id usage to make tests pass
added last() method to array prototype
corrected logic for inserting new transaction items into the account rollup list
[#68924438] added 'download prices' feature
[#68924438] added PricesController#download
[#68924438] added PricesDownloader and started the spec
[#68924438] added logic to PriceDownloader to get pricess from an agent and save them
[#68924438] finished changes to PricesController
[#68924438] finished making 'download prices' feature pass