Removed 15 more exception classes.

    ExtraMarkError
    ExtraNamedComponentError
    ExtraNoteHeadError
    ExtraPitchError
    InstrumentError
    MissingInstrumentError
    MissingMarkError
    MissingNamedComponentError
    MissingNoteHeadError
    MissingPitchError
    SpannerPopulationError
    TempoError
    TieChainError
    TonalHarmonyError
    TupletFuseError