Some changes to column sorting methods

Simplified some methods involved in column sorting.
Slight change column order UI.
Using control key instead of shift (can't change it back...not really relevent)
Left click on ordered column inverts direction. Crtl+click in ordered column removes it form sorted colunm list. Left click on unsorted column makes it the single sorted column. Crtl+click in unsorted columns adds it to list obviously.
This change permits removing all sorting and revert to natural order that wasn't possible earlier.
Been using it for more than a week but only now managed to integrate in github.