Fix relative path handling in cache_file
remove accidentially added "require pathname"
Use File.expand_path relative to global_config.root_path
Do it in validate, since that's the first time we have access to global_config (I think)
fix tests to include reference to env.root_path in vslidate phase
Merge branch '125_relative_paths' into 123_machine_config_berksfiles
defer assigning default values until finalize to better propagate changes in multi-vm vagrant setups