Add bind_unbound_port: necessary for device frontends

A frontend will typically bind an 'unbound' port which is set to
await an interdomain connection from a specific remote domid
(the backend).
Merge pull request #4 from djs55/master

Resynchronise grant table API with mirage
Add xenctrl.lwt containing the user-space activations module
Add missing file
Merge pull request #5 from djs55/activations

Add xenctrl.lwt containing the user-space activations module
Merge pull request #3 from djs55/add-bind-unbound

Add bind_unbound_port: necessary for device frontends
Merge pull request #6 from djs55/activations

Add missing file
Remove the top-level binding which called Eventchn.init

This causes obscure 'open failure' errors if /dev/xen/evtchn can't
be opened.
Merge pull request #7 from djs55/activations

Remove the top-level binding which called Eventchn.init