Added contact_creation_allowed option to the application
	* setup script support
Show/hide Contacts tab in the tabmenu based on the app setting
Restrict customer create/edit/delete based on app setup.
Restrict user create/edit/delete based on app setting.
Cukes for enable/disableb contact menu.
users_controller spec for disabled contact creation
customers_controller spec for disabled contact creation
Add default value of Settings.contact_creation_alloved for travis
Existing customers can be edited if creation disabled
Merge pull request #10 from digitalnatives/disable_contact_creation_option

Contact creation can be disabled via application wide option