relax SVN archive

ported r2634,r2636 & r2716 to the test-suite branch, corrected
test_float.py

commands used
svn merge -r2633:2634 svn+ssh://varioustoxins@.../svn/relax/1.2
svn merge -r2635:2636 svn+ssh://varioustoxins@.../svn/relax/1.2
svn merge -r2715:2716 svn+ssh://varioustoxins@.../svn/relax/1.2

these changes add the ieee-754 nan/inf code and nan catching from branch 1.3

reversed merge of ported r2634,r2636 & r2716 in r2717 to separate them
from the patches to float.py

https://mail.gna.org/public/relax-devel/2006-11/msg00053.html

Spell check of the PDB and PyMOL user functions and generic_fns code.

Added extra atoms to the 'AXS' residue of the tensor PDB representation for labelling.

Two or six extra atoms are added for the spheroid and ellipsoid axes respectively. These are set to
be nitrogen atoms to allow easy selection of just those atoms. They are also placed 3 Angstrom
outside of the geometric object so that the labels do not clash with the latitudinal and
longitudinal lines as well as the Monte Carlo simulation axes.

The code for generating the PDB chemical formula in 'self.write_pdb_file()' was modified to handle
nitrogen atoms.

The PyMOL user function 'pymol.tensor_pdb()' has been modified to use the new representation. The
final selection is also deleted at the end of the user function.

'pymol.tensor_pdb()' has been modified to change the representation of 'COM', 'AXS', and 'SIM'.

The centre of mass 'COM' is shown as the 'dots' representation and is coloured blue.

The diffusion tensor axes 'AXS' are shown as the 'sticks' representation, is coloured cyan, and the
atoms labelled to show 'Dpar', 'Dx', 'Dy', and 'Dz' in PyMOL.

The Monte Carlo simulations axes are coloured cyan.

Added a description of the 4 residues 'COM', 'TNS', 'AXS', and 'SIM' to 'pdb.create_tensor_pdb()'.

Removed the unused arguments to the 'self.write_pdb_file()' function.

Monte Carlo simulations are now included in the diffusion tensor PDB representation.

If Monte Carlo simulations exist and the diffusion tensor parameters were allowed to vary then the
PDB file of the diffusion tensor representation will contain multiple 'SIM' residues, one for each
simulation. The atoms of these residues represent the axes of the simulated tensors and they will
appear as a distribution.

The code for generating the 'AXS' residues has been shifted from 'self.create_tensor_pdb()' into the
functions 'self.generate_spheroid_axes()' and 'self.generate_ellipsoid_axes()'. The code has been
modified to create the 'SIM' residues as well.

Preparation of the other functions for automatically generating diffusion tensor data objects.

All the other functions (vs. the previous commit) have been prepared to return either the real value
or the MC sim data.

Simplification of the functions for automatically generating diffusion tensor data objects.

The following functions have been coalesced into their non-simulation counterparts:
self._auto_object_Dpar_unit_sim()
self._auto_object_Dx_unit_sim()
self._auto_object_Dy_unit_sim()
self._auto_object_Dz_unit_sim()