Big broken commit.
It's dirty but it works. List scalar and element-wise operations are
both implemented in the improved form. There remains a problem with
casting (what happens if you do :int32 + Fixnum? Is result :int32? or :int64?)

The good news is that slice-by-reference is working for the new
functions in list storage.
Merge branch 'master' of github.com:SciRuby/nmatrix