Importing SDSS_Catl_Utils

In order to encourage consistency amongst users in importing and using SDSS_Catl_Utils functionality, we have put together the following guidelines.

Since most of the functionality in SDSS_Catl_Utils resides in sub-packages, importing astropy as:

>>> import sdss_catl_utils

is not very useful. Instead, it is best to import the desired sub-package with the syntax:

>>> from sdss_catl_utils import subpackage