* update licenses for 2019

* style

* use line comments instead of multiline comments for license header

* update more

* update new files

* more header updates

* style

* remove reference to ngraph core code from codegen. add stand-alone implementations of needed funcions

* fixed potential pointer leak

* clean up file_util

* more file util cleanup, removing unused functions

* interpreter works on mac

* CPU and INTERPRETER build and pass unmit tests on macos

* move get_directory to file_util

* cleanup