trimmed fat from cyclus.rng.in
finished rng cleanup. Modified xml_file_loader to build/initialize from new schema paradigm
fixed rng problems by adding fac,inst,reg specific optional content. fixed init errors by adding InitFrom to reg and inst classes. other minor fixes
added missing member far to facility model initfrom
tmp - refactoring xml file loader
refactor - flat loader is subclass of regular loader
added cli flags for toggling flat schema and for manually specifying schema file.
doc comments and style tweaks
fixed unflag schema paths var init
renamed builder member var and made it protected so that subclasses can copy it in their InitFrom method for proper cloning