add shebang for py2 , because py3 may be not working

[KM-200]

py3 was not working for me.

[coveralls]

Coverage remained the same at 74.585% when pulling a409336 on KM-200:patch-1 into 9474e66 on jarvisteach:appJar.

[jarvisteach]

You'll need to raise the pull request against the next_release branch.

I also think it should just be python instead of python2

And it should probably be done in all files in the examples & issues directory?

[KM-200]

I am the last one to disagree... my latest bash script version does not corrupt the sources anymore as far as I know.

However, it seems to me, most current distros (say ARCH Linux) run py-3 when "python" is launched, but here "python2" is required specifically, unless the real problem is identified and fixed. Hence my "python2" shebang.