Changes

The user functions provide a simple interface to the relax backend. For plotting and most functionality, this is in the [http://www.nmr-relax.com/api/3.3/pipe_control-module.html pipe_control package] which is used primarily to read and write data to the relax data store.  However power-users can bypass the user function interface and directly use the backend code for greater functionality. This also allows for the implementation of new features without modifying the user interface. To use the backend code, you need to import: