Proposal: Services_ExchangeRates

I've changed the name of my currency conversion package yet again, this time to Services_ExchangeRates. I think that makes more sense than just Services_Exchange, since everyone knows what "exchange rates" are, but might not associate "exchange" alone with that. I've incremented the version number to 0.4, with the following changes: * Implemented conditional GETs with HTTP_Request and Cache_Lite * Improved file retrieval/caching methods in Common.php * Allowed default settings to be overridden with $options parameter in the constructor * Added dependency on HTTP_Request * Added dependency on Cache_Lite * Removed dependency on Cache Only 2 more +1s needed. :) -- Marshall Roch