* travis: move build flags tests outside of hardware header
* mqtt: fix typo
* travis: use files instead of bundling test cases into script
* fixup! travis: use files instead of bundling test cases into script
* fix variable expansion, remove custom h at the end
* add ade7953 to sensors list
* custom.h path as variable
* shellcheck
* fix printf syntax, silent again
* fix bash 4.3 treating empty array as unset variable