create custom learning material validator class.

[stopfstedt]

http://symfony.com/doc/current/cookbook/validation/custom_constraint.html#class-constraint-validator

[stopfstedt]

http://stackoverflow.com/questions/24325282/how-to-dynamically-control-the-validation-of-a-form
http://stackoverflow.com/questions/26550521/unit-testing-validator-constraints-with-symfony2-3

[stopfstedt]

validation matrix - lm field/lm type.

property name	db column name	all	citation	link	file
id	learning_material_id	x
title	title	x
description	description	x
copyrightPermission	copyright_ownership	x
copyrightRationale	copyright_rationale	x
uploadDate	upload_date	x
owningUser	owning_user_id	x
originalAuthor	asset_creator	x
status	learning_material_status_id	x
userRole	learning_material_user_role_id	x
token	token	x
citation	citation		x
link	web_link			x
mimetype	mime_type				x
path	relative_file_system_path_location				x
filename	filename				x
filesize	filesize				x