bug#9917: 24.0.90; Make `goto-line' consistent with the line number from the minibuffer

[Drew Adams]

> when someone says "see the line 42 in window.c"
> then `goto-line' should visit by the absolute line number, 
> ignoring any narrowing in effect.  But when someone says
> "see the line 42 in the Info node" then it should be relative
> to the node's beginning.

For `goto-line':

Let a negative prefix arg use line numbering wrt the restriction (region), and
let a positive prefix arg use line numbering wrt the buffer (widened).

Likewise for a number read at the prompt: negative for restriction numbering,
positive for full-buffer numbering.