[RFC v2] ff-memless-next driver

[Michal Malý]

Revised patch with "ff-memless-next" driver. Changes to the previous version
include:
- Fixes for a few bugs and corner cases
- More robust checking whether ff effect parameters are sane
- (Hopefully) fully in accordance to MS DirectInput specs
- Reworked triangle wave calculation
- Added documentation file

I tried to cut the lines to keep the 80 chars limit, but in some cases it was
not possible without compromising readability...

Tested-by: Elias Vanderstuyft <elias.vds@xxxxxxxxx>
Signed-off-by: Michal Malý <madcatxster@xxxxxxxxx>
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