Moved sorting to helper method

sorting done with assistance from rails cast video
http://railscasts.com/episodes/228-sortable-table-columns
Up down arrows to show sort order,

Adopted from Rails cast http://railscasts.com/episodes/228-sortable-table-columns
Added visual arrows displaying sort order
added protection from injection with private methods and params
removed extra space causing error message
Added logic for sorting the columns either accending or decending

Adopted to work from Rails Cast
http://railscasts.com/episodes/228-sortable-table-columns
Changed page title tag to reflect new project path CRM not invoicing
To Do stuff checked of (sorting customters)