DESIGN - REFACTORING - GILDED ROSE - removed superficial C Sharp code.
DESIGN - REFACTORING - GILDED ROSE - Made the program run. None of the test passes as of now.
DESIGN - REFACTORING - GILDED ROSE - Created classes for each type of the item that we are dealing with.

Base Item class comes up with Update, UpdateSellin and UpdateQuality methods, which can be leveraged by the specific item classes.

This is basically what we are doing.
DESIGN - REFACTORING - GILDED ROSE - Added a visual studio test project.
DESIGN - REFACTORING - GILDED ROSE - All the tests pass. Yay, and there are ton of them.

They might not cover all the scenarios still, but meh and good start.
DESIGN - REFACTORING - GILDED ROSE - All the item classes are moved to there own files.

This though is a clean operation, but it might frustrate who ever is reading code without a good IDE like VS 2013.