remove print statements that got left in

And made it through code review!!!
splint out render and write so we can reuse the render
suport variables in vars files of overlays
support file->directory copies in overlay
make overlays synchronous

People seem to expect overlays to happen in order. This patch changes
overlays such that they happen one at a time.
make directory checking more robust
support the ability to *not* autogenerate start scripts
add missing erlydtl to the escript created
make sure file permissions are set correctly in overlay template/copy
support 'to' dirs for mkdirs, templates, and copies being based on output dir
only allow relcool to take a single config
fix bug in usage of root dir in prv discover
support only one config file in the system
support config relative directories in templates and copy
support the ability to specify a root directory
use relative root for overlay vars file path
fix bug in goalless configs
add tests to try and cover unexpected failures
minor format refactoring
provide the erlang lib dir and cwd as working libraries

This happens for every call unless the user passes
--disable-default-libs to relcool or {disable_default_libs, true} in
the relcool config.