Modified url

1. changed bootstrap-url 'https://rawgithub.com/twbs/bootstrap/master/dist/'

2. changed jCanvas-url 'https://rawgithub.com/caleb531/jcanvas/master/'

3. fixed chrome-developer-tools-javascript-console warning 'event.returnValue is deprecated. Please use the standard event.preventDefault() instead.'

4. changed rackplan.js-url 'https://rawgithub.com/izawa/rackplan.js/master/'