Remove -u/--undo option for enabling 'undo' features, making them active by default

Original nano commit: 4964
http://svn.savannah.gnu.org/viewvc?view=rev&root=nano&revision=4964
Original nano commit message:
	Removing the --undo option, having the undo functions always enabled.
	If wished, the user can unbind them.  This fixes Savannah bug #42456.
Update spec file
When uncutting a backwards cut, put the cursor in front of the uncut text

Original nano commit: 4966
http://svn.savannah.gnu.org/viewvc?view=rev&root=nano&revision=4966
Original nano commit message:
	Putting the cursor back in front of a backwards cut,
	where it was when the cut was made.
	Patch by Mark Majeres, edited by Benno Schulenberg.