relax SVN archive

Fix for the documentation bug #7402 (https://gna.org/bugs/?7402).

This fixes the sigma(NOE) equations in section 8.8.1 of the relax user manual. Alex Hansen reported
that the equations incorrect as one of the spectral density terms were multiplied by a factor of 6
when there should be nothing. This problem does not affect the code, the equations there are
correct.

Removal of the installation targets and changing of the initialisation of the system path variables.

The installation target functions 'self.install()' and 'self.uninstall()' have been deleted as they
are now located in the 'scons.install' module.

The 'self.paths()' function has been removed. All the paths, environmental variables, etc. are now
initialised at the top of the 'sconstruct' file.

Shifted the 'install' and 'uninstall' target functions into their own module in the 'scons' dir.

The fix of the previous revision has been redone.

Rather than 'sconstruct' passing in the relax version number as an environmental variable, the file
'scons/distrib.py' now just imports the file 'version.py'. This is a much simpler solution!

Fixed a bug in the Scons distribution target functions.

The relax version number variable 'version' which exists in the base 'sconstruct' module doesn't
exist within the 'scons/distrib.py' module. It is now passed into the construction Environment as
an environmental variable.

changes to correct unicode errors from float.py and include nan and inf
checks in model free calculations

bug #6503 Uncaught nan in xh_vect from bugman

task #3621 overview: NaN catching function.

Shifted the Scons distribution target functions from 'sconstruct' to 'scons/distrib.py'.

The functions 'self.package' and 'self.gpg_sign' have been shifted into their own file
'scons/distrib.py'.

Initial checkin of code to work with ieee-754 double classes (nan etc)

bug #6503 Uncaught nan in xh_vect from bugman

task #3621 overview: NaN catching function.

Ported r2618 to r2632 from the 1.2 line.

The command used was:
$ svn merge -r2617:2632 svn+ssh://bugman@.../svn/relax/1.2

These changes all relate to the Scons system. The Scons scripts have been completely overhauled.
Bugs have been removed. The help system has been redone. A target for creating the API
documentation using Epydoc has been added.

Fixed a very minor bug in the Scons source packaging target.

The relax version was not being checked because the Depends statement was using 'package_bin' rather
than 'package_src'.