debian/base: Do not show stdout when updating apt index
Set bash option errexit for all scrripts which will cause the script to immediately exit if any subsequent commands fail
debian/common: Rename variable PACKAGES to COMMON_PACKAGES
debian/php-phpinfo: Rename variables
debian/common: Allow setting used variables via environment variables
debian/php-phpinfo: Allow setting used variables via environment variables
debian: Add missing symlink to common script for debian-8
test: Add test framework