[access] export some APIs,and remove unnecessary lines.

[access] export some APIs,and remove unnecessary lines.
  + elm_access_object_register();
  + elm_access_object_unregister();
  + elm_access_text_set();
  + elm_access_text_get();
  + elm_access_cb_set();

These APIs are to use edje part, evas object as an accessible object.
and do not create access object, because access object would be created at run time.
This is different with internal API _elm_access_object_register();

SVN revision: 81659