WIP: use openzeppelin contracts

contracts/lib/utils/MerkleProofLib.sol

@@ -1,58 +0,0 @@
-// SPDX-License-Identifier: MIT
-pragma solidity >=0.8.4;
-
-/// @notice Gas optimized verification of proof of inclusion for a leaf in a Merkle tree.
-/// @author Solady
-/// (https://github.com/vectorized/solady/blob/main/src/utils/MerkleProofLib.sol)
-/// @author Modified from Solmate
-/// (https://github.com/transmissions11/solmate/blob/main/src/utils/MerkleProofLib.sol)
-/// @author Modified from OpenZeppelin
-/// (https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/utils/cryptography/MerkleProof.sol)
-library MerkleProofLib {
-    /// @dev Returns whether `leaf` exists in the Merkle tree with `root`, given `proof`.
-    function verify(
-        bytes32[] calldata proof,
-        bytes32 root,
-        bytes32 leaf
-    ) internal pure returns (bool isValid) {
-        /// @solidity memory-safe-assembly
-        assembly {
-            if proof.length {
-                // Left shift by 5 is equivalent to multiplying by 0x20.
-                let end := add(
-                    proof.offset,
-                    shl(5, proof.length)
-                )
-                // Initialize `offset` to the offset of `proof` in the calldata.
-                let offset := proof.offset
-                // Iterate over proof elements to compute root hash.
-                for {
-
-                } 1 {
-
-                } {
-                    // Slot of `leaf` in scratch space.
-                    // If the condition is true: 0x20, otherwise: 0x00.
-                    let scratch := shl(
-                        5,
-                        gt(leaf, calldataload(offset))
-                    )
-                    // Store elements to hash contiguously in scratch space.
-                    // Scratch space is 64 bytes (0x00 - 0x3f) and both elements are 32 bytes.
-                    mstore(scratch, leaf)
-                    mstore(
-                        xor(scratch, 0x20),
-                        calldataload(offset)
-                    )
-                    // Reuse `leaf` to store the hash to reduce stack operations.
-                    leaf := keccak256(0x00, 0x40)
-                    offset := add(offset, 0x20)
-                    if iszero(lt(offset, end)) {
-                        break
-                    }
-                }
-            }
-            isValid := eq(leaf, root)
-        }
-    }
-}

contracts/lib/utils/ReentrancyGuard.sol

@@ -1,34 +0,0 @@
-// SPDX-License-Identifier: MIT
-pragma solidity >=0.8.4;
-
-/// @notice Reentrancy protection for smart contracts.
-/// @author z0r0z.eth
-/// @author Modified from Seaport
-///         (https://github.com/ProjectOpenSea/seaport/blob/main/contracts/lib/ReentrancyGuard.sol)
-/// @author Modified from Solmate
-///         (https://github.com/Rari-Capital/solmate/blob/main/src/utils/ReentrancyGuard.sol)
-abstract contract ReentrancyGuard {
-    error Reentrancy();
-
-    uint256 private guard = 1;
-
-    modifier nonReentrant() virtual {
-        setReentrancyGuard();
-
-        _;
-
-        clearReentrancyGuard();
-    }
-
-    /// @dev Check guard sentinel value and set it.
-    function setReentrancyGuard() internal virtual {
-        if (guard == 2) revert Reentrancy();
-
-        guard = 2;
-    }
-
-    /// @dev Unset sentinel value.
-    function clearReentrancyGuard() internal virtual {
-        guard = 1;
-    }
-}

contracts/lib/utils/SafeTransferLib.sol

@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: MIT
 pragma solidity >=0.8.4;
 
-import { ERC20 } from "../tokens/ERC20.sol";
+import { ERC20 } from "@openzeppelin/contracts/token/ERC20/ERC20.sol";
 
 /// @notice Safe ETH and ERC20 transfer library that gracefully handles missing return values.
 /// @author Solady (https://github.com/vectorized/solady/blob/main/src/utils/SafeTransferLib.sol)