Fixes scripts and removes shellcheck warning suppressions.
* regexp warnings
* use ./*glob* so names don't become options
* use $(..) instead of legacy `..`
* read with -r to avoid mangling backslashes
* double quote to prevent globbing and word splitting
Since c597d591b56a2a9ed355c57a717d1b2ed4c31aa9 the release script uses
acbuild instead of actool, so purge all the references and have the
release script check for acbuild's presence instead.
