Fixed the bug in issue #9 where the gamepad plugin wasn't working properly due to recent changes in how browsers handle 'this' in certain (export) situations. Also improved the situation where browsers detect gamepad axis as buttons and think they're persistently "pressed" (aka "down").  This should resolve the situation where a "hold" is detected on gamepad buttons when it shouldn't be.
Fixed the bug in issue #9 where the gamepad plugin wasn't working properly due
to recent changes in how browsers handle 'this' in certain (export) situations.
Also improved the situation where browsers detect gamepad axis as buttons and
think they're persistently "pressed" (aka "down").  This should resolve the
situation where a "hold" is detected on gamepad buttons when it shouldn't be.

liftoff/HumanInput,liftoff/HumanInput