Linking extensions to BLAS

[amilsted]

Expokit and also the eps_maps_c module need BLAS. Get known working library paths and names from numpy/scipy configuration to avoid user config requirements.

[amilsted]

As of version 0.16 (current version is 0.17), scipy provides cython cimports for BLAS and LAPACK functions (fortran versions). The simplest way would be to just use, thus avoiding the need to link eps_maps_c against BLAS explicitly.

[amilsted]

However, expokit still needs to link to BLAS/LAPACK.