Clear goal range when selection is modified

Just like the cursor clears its goal column when it is moved in any
way other than vertically, the selection clears its goal range (the
range it will attempt to use when adding a selection below) when it
is changed in any way.

src/app/cursor.coffee

@@ -88,6 +88,7 @@ class Cursor
 
   clearSelection: ->
     if @selection
+      @selection.goalBufferRange = null
       @selection.clear() unless @selection.retainSelection
 
   getScreenRow: ->

src/app/edit-session.coffee

@@ -591,7 +591,7 @@ class EditSession
     selection = new Selection(_.extend({editSession: this, marker, cursor}, options))
     @selections.push(selection)
     selectionBufferRange = selection.getBufferRange()
-    @mergeIntersectingSelections()
+    @mergeIntersectingSelections() unless options.suppressMerge
     if selection.destroyed
       for selection in @getSelections()
         if selection.intersectsBufferRange(selectionBufferRange)

src/app/selection.coffee

@@ -156,7 +156,7 @@ class Selection
     range = (@goalBufferRange ? @getBufferRange()).copy()
     range.start.row++
     range.end.row++
-    @editSession.addSelectionForBufferRange(range, goalBufferRange: range)
+    @editSession.addSelectionForBufferRange(range, goalBufferRange: range, suppressMerge: true)
 
   insertText: (text, options={}) ->
     oldBufferRange = @getBufferRange()