Package to avoid allocations in some functions when using StaticArrays.jl

A possible compromise regarding type-piracy is to make it optional: exports a functions with a different name and provide an option to commit type-piracy.

This is what I have done in ThreadedSparseCSR.jl: [ANN] Announcing ThreadedSparseCSR.jl

By default the package exports functions tmul and bmul which provide an aternative to mul and *. If one wishes to do so, the package provides the option to do type-piracy by overwriting mul and * by tmul or bmul