Don't assume Eigen's storage layout

[intractabilis]

I recently experience issue #135. The reason of not respected boundaries turned out to be here:

if (phenocandidates.size())
    _solutions._candidates.at(r).set_fvalue(
        _func(phenocandidates.col(r).data(), candidates.rows()));

The expression phenocandidates.col(r).data() assumes that the column data is adjacent in memory, which in fact depends on the defaults of the Eigen library. Suggested fix (in eo_matrix.h):

typedef Eigen::Matrix<double, Eigen::Dynamic, Eigen::Dynamic, Eigen::ColMajor> dMat;
typedef Eigen::Matrix<double, Eigen::Dynamic, 1, Eigen::ColMajor> dVec;

[beniz]

Good catch, can you PR the improvement ? Thanks!