Allow external BLAS use with ifort

[milancurcic]

It's just a matter of adding appropriate compiler flag in CMakeLists.txt.

[zbeekman]

I have some ideas for improving the CMake build, and allowing use of MKL etc.

But, first: Is there a reason why you're setting the CMake min version to 2.8? CMake binaries are relocatable (user space installable) and super easy to fetch and install from Kitware's CMake website. I would recommend bumping that to something MUCH more recent.

[milancurcic]

If you have time to spare, please go to town with the CMake build, I have no idea what I'm doing there.

Is there a reason why you're setting the CMake min version to 2.8?

This originates from my first ever CMake build (datetime-fortran I believe). It worked then, and I didn't dare upsetting the build demons by changing that number.