relax SVN archive

Fixed the select.reverse() user function.

The generic_fns.selection.reverse() function still does not work as the spin_loop() function needs
to be implemented.

Bug fix. Removed the import of the now non-existant Selection class.

Wrote a unit test for the generic_fns.selection.reverse() function.

Converted all the class methods of the 'generic_fns.selection' module into functions.

The unsel_*() methods have been renamed to desel_*() and the functions alphabetically sorted.

Implemented the generic_fns.residue.delete() function (although it doesn't work yet).

This function has been coded to use the UCSF selection syntax as described in Gary Thompson's post
located at https://mail.gna.org/public/relax-devel/2007-01/msg00014.html (Message-id:
<f001463a0701071417w6bd7927cp8fdd052e698575ec@...>).

The function makes use of three new selection functions - tokenise, parse_token, and molecule_loop.
The first two are described at https://mail.gna.org/public/relax-devel/2007-01/msg00036.html
(Message-ID: <1168883717.7569.511.camel@...>). The last function is similar to the spin_loop
function described in the same post. All three are yet to be implemented (although stubs have been
created for the functions).

The RelaxError 'RelaxSpinSelectDisallowError' has been created to prevent spins from being selected
by the user function.

The unit tests for generic_fns.residue.delete() have been updated and two more added:
test_delete_all() and test_delete_shift().

Added to empty unit test modules.

Removed to unused comment lines.

Removed the 'if __name__ == ...' statements and added a copyright statement for Gary.

Removed the executable property from the test_float.py unit test module.

The command used was:
$ svn propdel svn:executable test_float.py

Copied the 'residue.py' files to implement the new 'spin' and 'molecule' user function classes.