#1 Support XML-based SEG files

[Gary Feng]

Right now the default way to display SEG grids in the
graphic window is to use the SEG files, one for each
trial.

In the past several studies I have used PowerPoint to
generate PNG files as stimuli. The VB script also
outputs an XML based SEG file, which is much better
than the flat SEG format.

TeView should support this new format, with a flexible
way to handle variations of it.

More later.