Use a std-based epsilon instead of an arbitrary one.
Use a std-based epsilon instead of an arbitrary one.

Also reorder the includes a bit so that system includes come
before Tuvok includes.

git-svn-id: 83c4c97093aeea62ac982fbfd516bf9db27f5c99@747 c36c8488-0289-0348-9b64-b301f74bd9a7

BlueBrain/Tuvok,BlueBrain/Tuvok,BlueBrain/Tuvok