Switch to C++17

There is no harm in doing this since we are not a client library and all
environments using this project should have c++17 compliant compilers at
this point.

Tested:
    Run through unit test suite.

Change-Id: Iceae5375fd69b1929e1c4e2c6c297d131c61de68
Signed-off-by: William A. Kennington III <wak@google.com>
3 files changed