relax SVN archive

Created the private __molecule_loop() method.

This is for looping over the individual molecules of the scientific data structures.

A few fixes for the atom_loop() structural API method (for Scientific).

Non protein/RNA/DNA molecules are now supported in the atom_loop() API method.

Readded the condition to catch if no molecules can be identified in atom_loop().

Improvements to the Scientific Python structural object atom_loop() method.

Multiple molecules of different types are now simultaneously supported.

Fix for the print out of the load_spins() function.

Now only when a new SpinContainer is created is the spin system information written to stdout.

Bug fix for the write_line() function.

Added the missing import of generic_fns.sequence.write_line().

Updated the load_spins() function to print out a list of spins appended to the data store.

Fix for the test_angles() system test. The spins are now loaded.