relax SVN archive

Impliments the io.file_root() function.

As suggested:
https://mail.gna.org/public/relax-devel/2006-10/msg00218.html

reconfigure for new system test and unit test framework

https://mail.gna.org/public/relax-devel/2006-10/msg00197.html

add the start of the new test suite infrastructure create unit_tests
system_tests in tests_suite, move relevant files, update relax so system
tests run and add a first (broken) unit_test

ported r2634,r2636 & r2716 to the 1.3 line

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 and add nan catching

tidied code and added comments, code is now 4 space indented

task 3621 https://gna.org/task/?3621

Created a branch of the 1.3 line for an overhaul of the test suite and to implement unit tests.

This is in response to the many discussions in the thread following Andrew Perry's post at
https://mail.gna.org/public/relax-devel/2006-10/msg00172.html (Message-id:
<c225763e0610292348w78ce48bfw2d0c6a41c72d0b@...>).

A good summary of the changes is given in Andrew's post at
https://mail.gna.org/public/relax-devel/2006-10/msg00192.html (Message-id:
<c225763e0610302038k55863c5ct165b68ffa4c0180c@...>).

Ported r2713 from the 'tensor_pdb' branch.

The command used was:
$ svn merge -r2712:2713 svn+ssh://bugman@.../svn/relax/branches/tensor_pdb/

This adds the text "re-run relax with the '--debug' flag" to the RelaxFault error class.

Added the text "re-run relax with the '--debug' flag" to the RelaxFault error class.

Added RelaxImplementError for raising an error when code is executed which hasn't been implemented.

The PyMOL macro functions now call this error.

Changed all references from Molmol to PyMOL in the PyMOL code. The macro fns raise RelaxErrors.

The 'self.macro_exec()' and 'self.write()' functions raise RelaxErrors saying that the functions
have not been implemented yet. The 'pymol.cartoon()' user function has been shifted to the top of
the function list in the 'prompt/pymol.py' file.

Implemented the 'pymol.tensor_pdb()' user function.

The numerous Molmol commands have been replaced by a single PyMOL load command.