Modifications to progress to Less error watching

Introduced a simple Notifier singleton which possibly may be used to
integrate error reports from Less to the HTML5 Notification API. At
present, it simply logs info messages to console.
Updated to beta 3

- Debugger now uses local copy of Less 1.7.0
- Included Less license beside Less library as stated here:
http://lesscss.org/#license-faqs
- Fixed issues with HTTP version. The http version been tested on
Mozilla Firefox, Opera Next, Opera, Google Chrome, Apple Safari 7.1 and
Apple Safari on iPad and iPhone on iOS 8.1
- Updated the debugger README on with notes on how to use the debugger
with http-server including info on how to prevent caching
- Simplified LessLoader which now has a deprecated status
- Updated DOM queries to use #querySelector and #querySelectorAll
instead of legacy methods