Support `@guvectorize`

[PokhodenkoSA]

Support for @guvectorize is missing.

Features:

• [ ] Passing intra-device arrays
• [ ] Launch asynchronous
• [ ] Calling Device Functions
• [ ] Explicitly control the maximum size of the thread block

Example:

@guvectorize(['void(float32[:,:], float32[:,:], float32[:,:])'],
             '(m,n),(n,p)->(m,p)')
def matmulcore(A, B, C):
    ...