2020-10-06 Old bitCNY parameters adjustment

[abit]

Purpose:
to restore the peg of bitCNY in the long run and mitigate the issue that some debt positions' collateral is too low.

Changes:
ICR has been increased from 245% to 275%.

Current parameters:

ICR 275%
MCR 175%
MSSR 150%
MCFR (Margin call fee rate) 5%
FSO (Force settlement price offset) 2%
FSFP (Force settlement fee percent) 1%

The median feed price is 0.22 CNY/BTS.
Note: the ICR value 275% for feed price 0.22 effectively means 175% for market price 0.14, and the corresponding black swan price is 0.08.

Borrowing has been enabled earlier. The maximum supply is limited to 35,000,000 bitCNY.