tr1 has isnan, and we require tr1 now.
tr1 has isnan, and we require tr1 now.

Allows us to get rid of all the hacky #ifdef magic, which I was
never sure was correct anyway.

git-svn-id: 83c4c97093aeea62ac982fbfd516bf9db27f5c99@1336 c36c8488-0289-0348-9b64-b301f74bd9a7

BlueBrain/Tuvok,BlueBrain/Tuvok,BlueBrain/Tuvok