Add bz task bundle cli tool

[jstty]

Something like

bz-bundle --type=sh --in=mytasks.js --out=bundle.sh

Would bundle all the js code into one single bundled file that is marked executable and wrapped to execute shell script (# !/bin/sh)
There is lots of ways the file(s) could be bundled/compressed as well. So an optimzation flag could be added later.