Added "Add to favorites" button to graph view
Added table view controller
Add "Favorites" tool bar button with popover segue to table view
Set table view properties
Showing calculator program description on table view
Remove checking for nil when getting favourites from user defaults
Added "y = " to favourite graphs
Use the same naming for programs table view delegate as in the lecture
Add functionality to remove a favourite graph from table view after swipe and delete button is clicked on table view row
Some changes in storyboard
Highlight "Add to Favorites" button when touched
Added favourite graph elements to iPhone storboard
Show the graph after selecting it in favorites