[release] Add a cpp flag to config.h if psurface is found in at least version 2.0

With this flag (which will not stay forever), I can enable the hdf5 functionality
of psurface-2.0 when it is available.
(cherry picked from commit 569117a6310d11d1a92ecc45881df755b7972da6)

Signed-off-by: Markus Blatt <markus@dr-blatt.de>
[release] Allow reading of psurface objects from hdf5 files

... if a new enough psurface is available.
(cherry picked from commit 7bd1f502e92111136d9daeb503f4bda7f5d2083a)

Signed-off-by: Markus Blatt <markus@dr-blatt.de>