[Kst] datasource paths in kst files

[Barth Netterfield]

In 1.x, kst stored the entire path to the data source in the .kst files.

Currently, 2.0 records the file path relative to the cwd (this seems bad to 
me).

Josh suggests that kst 2.0 records the file path relative to the location of 
the .kst file.

Thoughts?

cbn