Allow passing through a command line option of '-'.
Allow passing through a command line option of '-'.

This is the normal UNIX convention to mean `read from stdin'.
We're overloading it to mean `output to stdout'...

git-svn-id: 0a20d38d1bcdb3210d244a647211d61b0aabf366@16 5b8196f7-c1c0-4be6-8b13-4feed349168d

BlueBrain/Tuvok,BlueBrain/Tuvok,BlueBrain/Tuvok