added conversion to data frame

For recent changes, we have tried to respect the class of `x` for new
data. For these models, the model fitting function and/or the
prediction functions require data frames.
a bug was fixed related to parsing model names
archived packages now ignored for testing
significant changes

Test cases were added to test the formula interface.

In several cases, the regression model data was changed to a simulated
data set (instead of the BBB data).

The predictor set and/or samples sizes of the test data were changed in
some cases.