Add deep copy to Range

src/atom/range.coffee

@@ -1,4 +1,5 @@
 Point = require 'point'
+_ = require 'underscore'
 
 module.exports =
 class Range
@@ -13,6 +14,9 @@ class Range
       @start = pointB
       @end = pointA
 
+  copy: (range) ->
+    new Range(_.clone(@start), _.clone(@end))
+
   toString: ->
     "[#{@start.toString()} - #{@end.toString()}]"