DX4

Implement DIPROP_DEADZONE for joysticks.  (Think about how this afects
passive access.  Can we do dead zone locally, thereby allowing each app
to set its own?)

Return better error codes when somebody tries to some thing bad to
something that can't be done.  E.g., E_ACCESSDENIED for trying to
change granularity.

Implement per-axis rel/abs modes.

Implement recent-down recent-up states.

DIPROP_RESTPOS  - rest position for an axis or button

VxD: Don't signalunless key is in the current data format

Note:  NT returns C5 as scan for numlock instead of 45; returns 45 for Pause.

Still some holes in DIERR_INPUTLOST during forced unacquisition due to
loss of foreground.

DX6 - Allow setting joystick range where min > max to reverse sense.

DX5 - disable HID goo