TouchDraw 1.3.1

New Features
   * Added the ability to export drawings as Visio documents.
Useability Enhancements
   * Updated the path bounds to not include the handles (iOS 4.2 or newer).
Bug Fixes
   * Fixed an issue with converting the clipboard contents to an image on exit.
   * Fixed an issue when toggling layer visibility while editing the layer names. 
   * Fixed an issue with removing figures from a layer.
   * Minus signs weren't previously allowed in the numeric text fields.
   * Fixed an issue with removing all of the layers leading to the layer stack being corrupted.