include ActiveModel::Model

Avoid parameter lists longer than 5 parameters.
Make use of validations
test for validations
use the new ActivityCreator API
move the create activity logic to a new method
remove some unneeded documentation
define the RecordInvalid class
fail if the record is not valid
remove pending example
add a few more examples for ActivityCreator
move RecordInvalid to lib/socializer/exceptions
require exceptions
removed from the ActivityCreator class