Updated source for Van der Waals radii.

Implemented new Van der Waals radii in atomprop. This may
have an effect on results from gmx sas or editconf and therefore
a message is printed to notify the users of this.
The genbox program is adapted to have an extra option to scale
the Van der Waals radii, in case it is difficult to add extra
atoms. The default value for this option is 0.57 which gives approximately
the same density as old genbox.

Change-Id: Ib5d86a920ae7732ee8a29505449e6d34e3d3980c
Merge "Updated source for Van der Waals radii."