[Kst] CDF version 3.0 MUCH faster !

[Brisset, Nicolas]

CDF is a nice and compact format, and the CDF datasource in kst works
quite well. But there is one thing that had always been annoying: the
_very slow_ opening of CDF files, at least with some versions of the CDF
library (2.7 for example). Some experiments had already allowed to
reduce the time taken to open our cdf files from 120 s to 15 s, and I
have just tried the recently released V3.0, where opening CDF files is
almost... instantaneous :-)
I can only recommend to people using CDF files to upgrade to CDF V3.0 if
possible (files from older versions are supported for reading/writing,
but newly created files will use a new format that cannot be read with
older versions of the CDF library).

Nicolas