Doesn't work with SDK 1.5.1

[atwoz]

Hello nqd, I managed to compile all fine with the new SDK 1.5.1 but it's not compatible with your makefile since the gen_appbin.py file now uses a new parameter (app) which I think only has 3 possible values, 0, 1 and 2. This is coded into the binary so that when the App is downloading the binary it checks to see if it is valid, if it is not it gives an error. I can help you get this working. Send me a personal msg so we can talk via skype or something. Thanks a lot.

[nqd]

Great thank @atwoz.Could you please create a PR for this? I am quite low bandwidth nowadays and don't work dirrectly with the esp.Bests.