Updating process list in response to user (MenuRefreshCB)

The MenuRefreshCB callback updates the process list when the user selects Refresh from the View menu.

This callback obtains the handle of the list widget, then calls the DoRefresh procedure. To accomplish this, MenuRefreshCB:

1. uses keylget(TCL) to obtain the form dialog from the cbs keyed list

2. calls VxGetVar(VTCL) to obtain the list widget attached to that form dialog

3. passes the list widget to the DoRefresh procedure