Fix base install on CentOS 6

A few fixes and tweaks to make installing on a CentOS 6 system functional and pretty.  Functionally, the conditional logic on $manage_perl needed to be looking for a boolean.  Aesthetically, refactored to give a File default and remove directory->file dependencies that are already implicit.  Moved params.pp to best-practices location in main manifests/ directory.  Usability-wise, changed manage_perl to default to true, since it's a rare situation when a user won't want the package installed by our module.