Dont rely on '\n' in echo statements

[jdtimmerman]

As mentioned in #169, some are having some issues with the transpiling. Appearantly there are different implementations of echo that may behave differently. According to the (not really) official documentation, printf may be a more reliable alternative.

[mebjas]

Thanks for the PR, added a single comment.

Thanks!

[jdtimmerman]

Ok, how about this. Instead of mixing printf's and echo's, I used multiple echo's. This gets rid of the not-universally-supported \n's but still keeps a consistent use of applications.
I've also changed how ZXing is added for consistency and with a little documentation comment

[mebjas]

Looks good to me, thanks, merginig!