Conflicts:
	lib/cancan/ability.rb
	lib/cancan/active_record_additions.rb
	lib/cancan/can_definition.rb
	spec/cancan/ability_spec.rb

Main goal is to allow:

cannot :manage, :all
can :read, :all
can :manage, User, :id=>user.id
can :manage, User, :manager_id=>user.id

Signed-off-by: Sokolov Yura <funny.falcon@gmail.com>

allow access to classes when using hash conditions since you'll generally want to narrow it down with a database query

removing unauthorized! in favor of authorize! and including more information in AccessDenied exception - closes #40

renaming ActiveRecordAdditions#can method to accessible_by since it flows better and makes more sense

adding caching to current_ability class method, if you're overriding this be sure to add caching there too

default ActiveRecordAdditions#can method action to :read and use 'scoped' if 'where' is not available

adding can method to Active Record for fetching records matching a specific ability, still needs documentation