New : Added composer.json

Added composer.json file which will help this module for submission on proposed extension.silverstripe.org website. Please add more fields according to requirements.

For more information please visit at http://extension.openbees.org/instructions/
Merge pull request #1 from vikas-srivastava/composer

New : Added composer.json
Merge pull request #3 from jedateach/patch-1

updated README with proper way to introduce the validator
Updated IpAddressRestrictedGroup class to be compatible with SS3.1