Bumped Backbone.js version to 1.0.0 in zentasks examples

 - Bumped Underscore.js to 1.5.1 because 1.4.3 or higher required.
 - Fixed main.coffee
  -- I changed @el to @$el because @el isn't a jQuery object in 1.0.0
  -- AppRouter's routes doesn't work. They shouldn't start with "/" in 1.0.0
Merge pull request #1338 from seratch/scala_zentasks_backbonejs

Bumped Backbone.js version to 1.0.0 in zentasks examples