Change issuer on record

[wanderingbort]

This is a pulled back version of Smart Property Administration allowing for the rotation of issuer address for long lasting crowdsales and manually issued properties.

These properties live long enough that good security practices would require the address which possesses administrative power to rotate and stay fresh.

This does not preclude a future more fully featured SP administration layer, as any system would necessarily need to allow a change of issuer.

NOTE: there is one omission in the revoke manual issuance transaction where the wording was not changed to respect the issuer on record. This is because PR #256 removes that clause entirely and I did not want to cause merge conflicts

[dexX7]

Some time ago when I was thinking about Mastercoin based options I noticed the mechanism is almost given, spec wise, and it would only require small changes to come up with an explicit "american option" transaction type where the traditional DEx is used, but with longer payment timeframes and the "spam/commit-fee" would be required to be sent to the seller, instead of the miners, as the option's premium while no partial payment would be granted.

But then I envisioned: it would be neat, if such options were tradable on the meta-DEx at some point in the future or could be transfered to other users in general. The idea I had back then was to issue a special token once an "accept" transaction (in this case to "buy an option") confirmed. This special token would represent the "has-accepted-offer/has-bought-option" state and the token would vanish, once the option is exercised or a trade finalized (in the case of the traditional DEx).

I quickly dismissed the idea, given that the whole options idea hasn't received approval and the complexity that "state/ownership" tokens come with.

Since this PR tackles the topic "transferable ownership" directly and SP administration isn't a crazy idea anymore, I'd finally like to bring up the idea of using tokens to represent "ownership", "right to do x" and state in general.

In this particular case a "property administrator" token would be granted to the issuer of tx 50, 51 and 54 and instead of using tx 70 to entitle a new "issuer on record", this "property administrator" token could be sent to the new "owner".

[ghost]

I can confirm this code works

(TX: https://blockchain.info/tx/267de4efbb603b0a1cbcef20b1cde5fb4969772a07ef421304b887643766fc1f - Transferred ownership to a new address, Did a grant for +1 Mgd properties, balance for that property is now +1 and the Issuer has changed, using Bart's branch)

[dacoinminster]

Hmmm. I'm told this is actually in live code now? Guess it's time to merge!