Revert "stop reading fonts/input plugins from environ as we now have a working mapnik-config.bat on windows"

This reverts commit d87c71142ba7bcc0d99d84886f3534dea7617b0c.
Revert "stop reading fonts/input plugins from environ as we now have a working mapnik-config.bat on windows"

This reverts commit d87c71142ba7bcc0d99d84886f3534dea7617b0c.
unbreak tilemill packaging tricks
fix gen_settings.py
merge