* Simplified all_close_f tolerance determination. Made all_close_f less verbose. Transitioned graph comparison to use double comparison when appropriate.

* Reworked all_close_f AssertionResult returning code to include message in AssertionResult on success also.

* Added CMake option NGRAPH_GTEST_INFO, which controls whether or not any gtest info cout is done. Quiets all_close_f tests by default.

* Moved NGRAPH_GTEST_INFO from build option to environment variable.