* doc updates

* test add section on transformers to graph basics

* Fix typo on abs

* Adding more background and detail for graph-building concepts unique to nGraph

* First pass at updating nGraph basics for StackOverflow kinds of questions

* Forgot to add a file

* Update for new naming and capitalization conventions

* add edits from first PR review

* More updates from PR review

* BatchNorm documentation

* Fix typo, install URL

* Switch to desired BatchNorm