add mathematica-9.0.1
Don't set a default version of Mathematica

Nixpkgs should not set a default version of Mathematica. Many users of
Mathematica have institutional licenses and do not have immediate access
to new versions. If there is a default version in Nixpkgs, updating that
version will cause trouble for all such users.
Merge branch 'arpack' into installed
Merge branch 'keepassx' into installed
Merge branch 'mathematica' into installed
Merge branch 'vobsub2srt' into installed
Merge branch 'shellInit' into installed