and while there also rename the bogus completing_read to minibuffer_read. To get a ``completing-read'' one has to call enter_minibuffer with the right parameters.

don't consider an invalid tab id as an error. Things are asynchronous, we may issue a request but then stop it, and still get data relative to that. So, ignore the request when we get an invalid id.

My original idea was to crash when receiving data for an invalid tab. This idea just doesn't hold well in an asynchronous context. If we change page before the current tab finished loading we issue tab_stop, but even after that we still could receive a IMSG_BUF for that old tab id.

don't load all the tabs when starting up, only the current one. Defer the loading of the others when switching to them.