Changed Gemfile & Rakefile, fixed errors on startup

update rvmrc to use 1.9.3

update Gemfile & Rakefile to start app
install rails_upgrade plugin and backup configuration files
upgrade routes.rb file
rails3-support gems + removed attachment_fu from vendor/plugins
move assets to app/assets directory
update rails environment configurations and static files
remove new_rails_defaults.rb, add rails3 wrap_parameters.rb initializer
changed configuration for session store
update .gitignore
update initializers and remove some ones
cleanup vendor/plugins, run application
gitignore uploaded files
named_scope -> scope in models
return values from form helpers to erb templates
add attr_accessible fields to image model
use attachment_fu from forked repo to be compatible with rails 3
renamed scope so that it does not raise undefined const_defined? method
add attr_accessible field to FeaturedImage
pass object to partial - rails 3 doen't look up instance variable in parent