Improved Experiment-to-Display Process

Experiment subclasses know which Display subclasses they're good for.

The existing Experiments were revised so they produce useful python
objects.

There is a new Display subclass (SpreadsheetFileDisplay) that takes the
output of those experiments, makes it into a CSV string, then outputs
it through the existing FileOutputDisplay class.
Simplified GUI

I removed many of the widgets on the "experiment" panel that are--at least
for now--not being used.

Choosing a different object for consideration (intervals, interval n-grams,
chord n-grams, and others later) automatically enables and disables
widgets on that panel.
Commented Unused GUI Widgets on "Experiment" Panel

So it doesn't crash any more.
Add __getitem__() to AnalysisRecord
Significant Revision in Experimenter
Support for "Salami" in GUI. Correct IntervalsLists Errors

- IntervalsLists deals with Rest objects
- IntervalsLists output is a bit more consistent
- "salami" is now sometimes called "repeat consecutive (identical)"
- Added new column to ListOfPieces for "repeat consecutive"
- Added new QCheckBox & signals/slots for "repeat consecutive"