Fixes to task implementation with escape option
Fixes to task implementation with escape option

Makes the following adjustments to the escape option handling:

- explicitly assign the mustache.escape reference to the original
  HTML-escaping function if 'escape' is set to true
- return the mustache.escape reference back to how it was once the
  target has finished running
- if the user passes an 'escape' that is not true or false, raise an
  exception

5thWall/mustache-render,jGleitz/mustache-render,jGleitz/mustache-render,5thWall/mustache-render