WIP on error reporting system

- add error reporting callback to Vtr::Level::validateTopology
- switch printfs to callback
- add error code enums to Vtr::Level
- route Far::TopologyRefinerFactory::reportInvalidTopology through Vtr::Level callback

note:
- Vtr::Level::validateTopology needs to check creaase tag indices
- topology validation should be client-code driver in TopologyRefinerFactory (turned off in the code at the moment)