adds edit button
return one extra row when in editing mode
sets content for "Add New Week" row
adds setEditing:animated: method

called when clicking on Done button
sets Style for "Add New Week" row

Delete for Week rows
Insert for “Add New Week” row
adds animation to insert the extra row

and also to get rid of it
adds functionality to delete week

remains to make API request
makes API request to DELETE week
style changes