Upgrades package versions and fixes installation errors.

[johannesjh]

Updates package versions to get the installation to work on MacOS 10.11.

• Uses Express 4
• Uses the older (!) backbone 1.1.0 because 1.1.1 breaks AMD compatibility, compare this issue https://github.com/marionettejs/backbone.marionette/issues/1249#issuecomment-41739400
• Fixes paths to d3.js in the gruntfile

Note: Additionally, to get the installation to work, I had to use a newer version of restify because I otherwise got node-gyp compilation errors, compare this pull request https://github.com/slashdotdash/node-ledger-rest/pull/2.