Otherwise this provider cannot be initialized from standalone Python
scripts
Fixes#36661
Also cleanup 3d sip generation by correctly defining SIP_NO_FILE
in headers we don't want to expose, so that the sip_include script
can do its magic
* update Travis to build on Trusty for code layout
* fix shellcheck replace ! -z by -n
* shellcheck: fix -n doesn't work with unquoted arguments
* more shellcheck fixes
* use bash instead of posix