fixes typo in memory view validation code

Newaxis support for memoryview slices & avoid taking address of memoryviews for utility functions

    todo: support memoryview object newaxis indexing

minor fused cleanups

    This breaks comparing typedef types and results
    in funky things such as getting temporaries of
    different types.

This reverts commit e3838e42.

fused runtime dispatch for buffers

Infer variable as pyobject when del-ed, fix #768