Revise LilyPondExperiment to Accept Field Descriptions in Results

Some Experiments produce field descriptions as the first element in their
results list, which used to screw up the LilyPondExperiment.
Added Some GUI and Experiment Things for Targeted LilyPond Output

- New QLineEdit for which n-grams to annotate.
- New setting in ExperimentSettings
- Template TargetedIntervalNGramExperiment for Alex.
- LilyPondExperiment chooses T_I_NG_E when it should.