Only define methods for sparse matrices when CHOLMOD is available.

[andreasnoack]

Fixes #43. This will most likely also drop support for 0.4.

[ararslan]

The @statics shouldn't be necessary at the top level, otherwise LGTM

[ararslan]

Looks like this is failing on Julia 0.4 since there's no SparseArrays submodule of Base. While I don't mind dropping support for 0.4 at this point, I wonder if this could be handled more effectively by putting all of the sparse stuff in its own file, then doing

if isdefined(Base, :SparseArrays) && isdefined(Base.SparseArrays, :CHOLMOD)
    include("sparse.jl")
end

in src/PDMats.jl.

[aviks]

Bump. Could we get this in please? This breaks about a dozen other packages (via Distributions) when run with a non-GPL julia build.

[aviks]

Thanks! @andreasnoack . Appreciate it. Is this ready for a new tag?

[andreasnoack]

Yes, I think so. I'll do it as soon as all tests have passed.