Make expokit shared library private (i.e. renamed to _expokit.so). Rename expowrap.py to expokit.py, providing public interface. Turn time_expm.py into a proper benchmark module (with unittests), and removed redundancy between time_expm.py and expowrap.py (now linalg.benchmarks.bench_expm and linalg.expokit). Sparse matrices still not working...