update Rakefiles for RDoc 2.5
update Rakefiles for RDoc 2.5

Shopify/activeresource,rjordan/activeresource,wyattisimo/activeresource,yui-knk/activeresource,1776/activeresource,om-nishu-trantor/activeresource,maclover7/activeresource,chadzilla2080/activeresource,rails/activeresource,repinel/activeresource,peterjm/activeresource,eileencodes/activeresource,SweeD/activeresource,delameko/activeresource