* Initial stab at Bulletproofs+
Does move around the existing Bulletproofs code, does still work as
expected.
* Make the Clsag RCTPrunable type work with BP and BP+
* Initial set of BP+ bug fixes
* Further bug fixes
* Remove RING_LEN as a constant
* Monero v16 TX support
Doesn't implement view tags, nor going back to v14, nor the updated BP
clawback logic.
* Support v14 and v16 at the same time
Saves roughly 0.8s when running the tests, which took 16.6s and now take
15.8 (5%).
Removes the larger sample size, which replaced the closest selected
decoy with the real spend, per advice of Rucknium.
Updates decoy selection with an explicit panic, the removal of a divide
by 0 (causing tests to fail on new chains), and a minor optimization
when dealing with a large quantity of locked outputs.
Also increases documentation, acknowledging infinite loops and breakage
from Monero more.
