Changes

* Bug fixes for a number of broken Oxygen icon lookups in the GUI.

* Bug fixes for the [http://www.nmr-relax.com/manual/molecule_delete.html molecule.delete], [http://www.nmr-relax.com/manual/residue_delete.html residue.delete] and [http://www.nmr-relax.com/manual/spin_delete.html spin.delete] user functions. The molecule, residue, and spin metadata in the relax data store was not being updated correctly after these user function calls so that any subsequent operations on this data was failing. This metadata problem was not noticed before as it disappears if the state is saved and reloaded into relax after a restart.