simplifying language in the why backbone section
tidying up line about state in single-page apps
cleanup of line on templating/JSON
fix for template example
correction regarding callback
dropping unnecessary vars for sync pattern
Some spelling and grammatical fixes.
Merge pull request #335 from aodin/gh-pages

Spelling and Grammar in Chapters 7, 8, and 9
Chapter 8 - Minor revisions/corrections

Also a typo correction in Chapter 14.
Merge remote-tracking branch 'upstream/gh-pages' into gh-pages

Conflicts:
	chapters/08-extensions.md
Merge pull request #338 from dcmaf/gh-pages

Chapter 8: Extensions - Some rewording and corrections
adding note about underscore methods
removing in-place editing line
fixes #340 - patch for thorax example
dropping mac/linux/win specifics for bb
updating line about yeoman
Switching order of chapters 7, 8 for #343
removing second image from Marionette walkthrough as part of #343
adding example of bbb output for #322 point 4
adding earlier description of Backbone.LayoutManager for #322 point 6