Support variable strength for rumble motors.
Add rumble support to XInput driver
Don't rumble if strength == 0.
Don't install 0-strength rumble effects.
Stop rumbling effects when entering RGUI.
(RMenu) Use rgui->selection_ptr
tweak xinput rumble
Merge pull request #310 from pinumbernumber/master

Add rumble support to XInput driver
Build fix.
Fix linebreak encoding in winxinput.
Freeze GET_RUMBLE_INTERFACE.

Interface should be good to go now.
Merge branch 'master' into configswap