0.0206
  optimize new methods

0.0205
  add mixins select options 
  
0.0204
  document is updated

0.0203
  remove many options 'type', 'setter_return', 'required'
  remove method 'error'
  add options 'chained'
  
0.0202
  mixin format is changed.
  remove _arrange_args and _init method
  
0.0201
  first release
  
0.01_02
rename Object::Simple::Error attribute 'pkg' to 'class' 
delete attribute key before pass args to _init 
remove no need files 
_arrange_args return hash ref, not hash 

0.01_01 first developer release