Update README file

ToC was added; link in step 4. of the setup was fixed; info about vagrant
version was added; info about version of bindler plugin was added; typos
were fixed.
Remove data bags from chef recipes; fix ping_example

The receipes unnecessarily used data bags that introduced redundant
complexity.
Merge pull request #1 from FlowForwarding/dev

Update README.md and simplify recipes.