Newer versions of CMake don't like at-symbols in variable names

[jameslittle230]

I'm trying to figure out some dependency issues in trying to get our code to compile on Ubuntu 16.04 and I'm running into an issue where CMake 3.1 doesn't like @'s in our variables due to a new CMake policy that must have been added recently. The workaround is to disable this policy but maybe we should think about refactoring our CMake options to both fix this bug and remove old options (color tables) that we don't use anymore.