Tags

A lot of refactoring and performance improvement.

- Simplified type signatures and implicits.
- There is still only support for vectors
- Benchmarks added and a lot of optimization done
- Automatic allocation of vectors; before these needed to be explicitly
passed to the API. Now these return Unit to make clear they are
side-effectful. Automatic allocation allows structural sharing.

First alpha release.

Tagless implementation of BLAS dense vector.