Change case of prefix and suffix to matched word

Previously an inserted automcomplete match would not
update the case of the prefix or suffix of the match
and instead only insert the text from the matched word
between the prefix and suffix.

Now the entire matched word is inserted as-is replacing
the existing prefix and suffix.

src/app/range.coffee

@@ -11,6 +11,11 @@ class Range
     else
       new Range(object.start, object.end)
 
+  @fromPointWithDelta: (point, rowDelta, columnDelta) ->
+    pointA = Point.fromObject(point)
+    pointB = new Point(point.row + rowDelta, point.column + columnDelta)
+    new Range(pointA, pointB)
+
   constructor: (pointA = new Point(0, 0), pointB = new Point(0, 0)) ->
     pointA = Point.fromObject(pointA)
     pointB = Point.fromObject(pointB)