framework -> library

Chapter 1 explains that Backbone is a library and not a framework, but the word **framework** slips in here and there. This pull request removes the word framework in places where it refers to Backbone or else changes it to something like "framework or library" when it is referring to Backbone and other things.

My editor automatically removes trailing white space, so that happened too. Probably best to view the diff with white space disabled. https://github.com/addyosmani/backbone-fundamentals/pull/579/files?w=1