Renamed AttributeBase to Readable
Attrio::COllections Array, Hash, and Set to use Readable and Collectable modules

moved attr_reader into Readable module.

removed InstanceMethods module from Readable

decided not to define initialize in a module.  This could be
readdressed.  If so, then the common initialize method needs to call a
class specific method for additional initialization.

moved Collection autoload block to the bottom of Attrio