[OoB-5.9]: Deprecation warning is not visible enough.

[ashok-rao]

The warning message must appear on the source files (main.cpp) as well for cases where not everyone in the outside world reads the README first :-) ..

Also, (side note) deprecation warning has been added to master branch. This is only a note but during OoB, changes are expected on the OoB branch and no further changes to master until the release.

[ciarmcom]

ARM Internal Ref: IOTSEC-700

[alzix]

fixed via 8b313c1