Feature request: Use the new task API for Cargo build, test etc.

[johanneshoehn]

Visual studio 1.14 arrived and supports extensions to define their own tasks dynamically.

Making cargo build, cargo test, etc. available as tasks through that API would allow for instance the standard keyboard bindings for building to work.

[KalitaAlexey]

It sounds interesting. I'll try to work with it in few days.