Update Git Slides

Add heading to VCS Comparison table
Remove commas if only two items listed.
Fix Backbone View/Model Events code sample

There is a bug in old code: after each book added render method called that append all old books and plus one new. So after each addition we duplicate all old books.
Merge pull request #39 from dmytroyarmak/master

Fix Backbone View/Model Events code sample
Updating Backbone Backend Model example to use 'urlRoot' instead of 'url' to match the intended GET request URL
Merge pull request #41 from JohnRiv/backbone

Fixing Backbone Backend Model example
Fix typo on Backbone Router slide
Merge pull request #42 from JohnRiv/backbone

Fix typo on Backbone Router slide
Merge pull request #37 from NanoXD/patch-1

Update Git Slides
Update strings.html

the previous parameter was non-standard.

It only changed the first occurrence of the first letter, it did not globally replace.
Merge pull request #46 from sundip/master

Update strings.html
Add missing li
Remove testing locally and videos.json reference
Updating API exercises
medium small
Adding OO slide deck
Changing JS MVC
Add examples of instantiation
Updating OO slides
Changed title
DIV to LI