relax SVN archive

Added a catch for zero Rx values.

Fixed the chi-squared function and 'func' now calls it.

Assigned the back calculated intensity to the external array 'back_calc'.

Added some sanity to the PyArrayObjects in the C code.

Pointers, eg 'relax_times' have been created to 'numpy_relax_times->data' and recast as double. Now
the elements of the array are refered to as 'relax_times[2]' rather than
'relax_times->data + 2*relax_times->strides[0]'. This should remove much pain.

Improved the makefile rules for compiling the C code.

Started to code the exponential back calculation function.

Added the C file for the back calculation of peak intensities in relaxation curve fitting.

More modifications to the relaxation curve fitting C modules.

The external variable *num_times, the number of relaxation times, has been added and is part of the
setup function argument list. The statement '#define MAXTIMES 30' has been added to the header.

The 'func' function has been updated.

The variables in the header have been sorted.

The compilation of the module has changed. Now the C files are compiled into object code *.o and
all the relaxation curve fitting code is linked into a single *.so file. These changes have been to
'maths_fns/Makefile'.

The base directory makefile has had it's goal modified to properly handle recursive making.

Debugging and addition of the function 'disassemble_param_vector()' to the relaxation curve fitting.

Bug fix:

The indexing involved in the automatic generation of the user function component of the manual has
now been fixed. The bug was causing not all instances of the key words to be indexed. Now all the
minimisation algorithms are indexed.