Get mean + quantile range from bootstrapped params.

def param_describe(params, quant=95, axis=0):
    """Get mean + quantile range from bootstrapped params."""
    par = np.mean(params, axis=axis)
    lo, up = perc(quant)
    p_up = np.percentile(params, up, axis=axis)
    p_lo = np.percentile(params, lo, axis=axis)
    return par, p_lo, p_up