`kraken_shell_scripts/kraken-build` difference with the original `kraken-build`

Hello @mw55309 ,

Thanks for this useful resource. 
Is it required to use the adapted `kraken-build` script?  Considering the Kraken upgrade to v1.0 as well as v2.0 beta..

Also since the KRAKEN_DIR is hard coded, it might worth to mention that it needs to be adapted in the readme.

Best,
Milad