**Added:**
- `Experiment` class is added as the new api of GlyTrait, instead of the old `GlyTrait`.
This might be part of the python package api in the future.
**Changed:**
- The formula file format is much simpler: any non-blank lines not starting with
"" will be parsed as a formula.
The formula descriptions are converted into comments (starting with "").
- `GlyTraitInputData` now checks the validity of data.
This allows dynamic change the input data after a `GlyTraitInputData` instance
is created.
**Removed:**
- `GlyTrait` class is removed.