WINTERMUTE: Struct'ify step functions
WINTERMUTE: Struct'ify setValue/Type
WINTERMUTE: Struct'ify readValue and remove printError()

printError() is, for all purpouses, superseded by getErrorDisplayStr()
WINTERMUTE: Add Error side effects to readRes
WINTERMUTE: Flesh out getErrorDisplayStr()
WINTERMUTE: Pass extra fields to get pretty error messages