relax SVN archive

Converted the load_spins() function to use relax_io.write_spin_data().

Removed all dependence on write_body() and write_header() from the sequence module.

Renamed read_spin_data_file() to read_spin_data() and write_spin_data_file() to write_spin_data().

Import fixes by shifting to relax_io.write_spin_data_file().

Deleted the write_body(), write_header(), and write_line() functions from generic_fns.sequence.

This should accelerate the switch to relax_io.write_spin_data_file().

Wrote the relax_io.write_spin_data_file() function.

This writes spin specific data to a file (can be STDOUT). It will replace the write_header()
and write_body() functions of generic_fns.sequence.

Removed some unused imports.

More fixes for the test_read_peak_list_generic(). It now passes!

Rewrote the intensity_generic() function.

This is now much simpler (5 lines of code).

Fixes for the test_read_peak_list_generic() system test.