relax SVN archive

Some fixes and improvements to the PyMOL macro related user functions.

Created the front end for the pymol.macro_run user function.

This will be used to open and execute macros from text files.

Renamed the PyMOL macro related user functions in the prompt/script front end.

The pymol.macro_exec() function is now called pymol.macro_apply(), and pymol.write() is now called
pymol.macro_write() to make it clearer.

A first trial at passing the "curve_type" to the C code.

However, something is wrong, potentially in the C code (see
compilation warning below) as relax now complains that
"an integer is required" for assignment to "curve_type":

====
maths_fns/relax_fit.c: In function 'setup':
maths_fns/relax_fit.c:66: warning: assignment makes integer from pointer without a cast
====

Anybody, any idea ?

The PyMOL macro file extension is now correct in the pymol.write user function GUI page.

Replaced "PyString_AsChar" by "PyString_AsString" as the former does not exist...

Fixed the problem whereas the symbol "_curve_type" was missing...

The PyMOL macro is registered as a pymol file in the results file structure rather than a Grace file.

The force flag now defaults to True for the molmol.write and pymol.write user function GUI pages.

Fixes for the pymol.write and molmol.write user function GUI pages.

The directory argument to the user function back end is now set to None as otherwise it defaults to
a directory such as 'pymol' which is then incompatible with the absolute file path from the file
dialog.