Use user env for shell scripts

[josephmilla]

[mattyjones]

@josephmilla This really cleans up the shell script, thanks!. What are your thoughts though on using a Makefile instead. I generally prefer Makefiles to shell scripts but am not overly concerned yet at this point. We then combine the build and release scripts into a single tool that is easily put into a CD/CI pipeline and just create multiple targets for each OS or action.

[mattyjones]

@josephmilla I merged this in tonight for the sake of it as the code makes a lot of improvements and I don't have the time to write a makefile at the moment. Thanks for this!