Found a problem with data sorting

Signed-off-by: Jonas Kalderstam <jonas@kalderstam.se>
Apply normalization to future data

If a model normalizes data during fitting, it should also
normalize data passed to the predict methods later in the same
way. As a logical consequence, CoxPH now stores the original data
instead of the normalized version as well as the normalization
variables.

I also added some checks to make sure that incoming dataframes have
the same input columns present as the fitting data. In case the incoming
data is an ndarray, the order is assumed to be correct (as before).

The following examples now work, where they before would crash or simply
return the wrong result:

    # fulldata has columns x1, x2, t, e
    cf.predict(fulldata)

    # shuffleddata has columns x2, t, x1, e, y1, y2, y3
    cf.predict(shuffleddata)

    # Xrev has columns x2, x1
    cf.predict(Xrev)

Signed-off-by: Jonas Kalderstam <jonas@kalderstam.se>