This commit moves the proprietary-relicensing 'poison pill' from the
basic copyleft provision (Distributing Derived Works) to a separate
section and broadens its effect. Now, if the original licensor ever
does proprietary relicensing, we say that none of the conditions on
distribution (nor the termination section) apply.
This applies only to the circumstance in which one distributes object
code in a physical product and opts to make source code available on
the net. The original choice of three years was based on the 3-year
duration of the written offer option in the GNU GPL.
I'm assuming a reduction from 3 years to 2 years here is not
controversial.
Some minor simplifications to the object code distribution section as
well.
I deleted the anti-anti-circumvention provision because I think it
needs to be redrafted from scratch.
