Visualise the file within Grace.
file: The name of the file.
dir: The directory name.
grace_exe: The Grace executable file.
This can be used to view the specified Grace `*.agr' file by opening it with the Grace program.
To view the file `s2.agr' in the directory `grace', type:
[numbers=none] relax> grace.view(file='s2.agr')
[numbers=none] relax> grace.view(file='s2.agr', dir='grace')