Tetu.io contracts update 1.6.0

These changes were made since version 1.5.0 and deployed during March-April 2022

Huge changes were made for moving OpenZappeling contracts to a local directory and implementing ControllableV2 for base contracts. These changes were needed for cheaper gas usage on ethereum.

https://github.com/tetu-io/tetu-contracts/compare/release-1.5.0...release-1.6.0

Base contracts

SlotsLib

A solution for managing contracts slots directly using byte32

TetuProxyControlled

Added additional protection. Now able to set implementation only with Controllable inheritance.

TetuProxyGov

The same controllable protection.

Announcer

Adopted for ControllableV2

Bookkeeper

Adopted for ControllableV2. Removed SafeMath.

Controllable

Replace OZ lib with a local file.

Controller

Adopted for ControllableV2.

ForwarderV2

Adopted for ControllableV2. OZ libs moved to local. Implemented temporally shortcut for BAL liquidation through Balancer pool.

FundKeeper

Adopted for ControllableV2. OZ libs moved to local.

VaultController

Adopted for ControllableV2. OZ libs moved to local.

ProxyStrategyBase

Added setBuyBackRatio

StrategyBase

OZ libs moved to local. Removed SafeMath.

Strategies

Minor changes for all strategies - moved OZ libs to local, rename some variables, removed SafeMath. Changed buyback ratio for some strategies.

BalStaking

A new solution for cross-chain farming ve tokens.

MarketStrategy

A solution for decompound supply profit for market.xyz

AMB strategy

Moved all contracts to proxies. Fixed some issues.

MB Strategy

Strategy for farming any assets on QiDAO. A part of AMB logic (without AAVE pipe)