Minor fixes and improvements

Here's a pull request for 3 changes. Feel free to choose to take back any of them : 
* I find it much more useful to get real file paths in my agent logs, as it makes it possible to quickly inspect files that the log references, without having to hunt for them first.
* Facts should be explicitly looked up as such and not be taken from the current scope.
* The module didn't work for me (puppet 3.3.2) with the message "Munging failed for value "undefined" in class replace: expected a boolean value", and changing the default for replace from undef to true fixes that.