Add LICENSE file via addalicense.com
Update LICENSE.txt
Update LICENSE.txt
Delete LICENSE.txt
Create LICENSE.txt

as suggested in http://choosealicense.com/licenses/bsd-3-clause/

based on license information given in https://github.com/2amigos/yiiwheels/blob/master/composer.json and https://github.com/2amigos/yiiwheels/issues/22
Merge pull request #29 from hallerma/master

add License