Clarified that the config.assets.initialize_on_precompile directive needs to be set in application.rb

[engines guide] missed a spot in the 'Using a class section' + further text for 'Configuring an engine' section

Include affected record when raising an ActiveRecord::StaleObjectError

small fix 

Remove user-specified delimiter from start when no area code is present (in number_to_phone)

Fix fragment cache helper regression on cache miss introduced with 03d01e

Fix fragment caching (squashed commits)

improved ActiveResource's .element_path and .new_element_path methods documentation by specifing how .site should be declared in order to use prefix_options

Added test to check that the vendor/assets/stylesheets directory is creat