Sample Return Codes

[nicholask42]

Modified samples to return EXIT_SUCCESS OR EXIT_FAILURE instead of 0 or 1. Also fixed incorrect return at the end of main method of basic.cc.

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[saran-t]

Thanks!

I'm afraid we'll need a CLA (https://cla.developers.google.com/) before we can merge this though.

[nicholask42]

Sorry for the delay @saran-t. I have completed the CLA, run the check again, and it has passed.

[yuvaltassa]

Fixed by 5187a71