cleanup precompile contracts (#53)

Author: PowVT

src/SovaL1Block.sol

@@ -13,22 +13,20 @@ import "./interfaces/ISovaL1Block.sol";
  * @author Sova Labs
  *
  * SovaL1Block provides information about the state of the Bitcoin chain.
- * Values stored in this contract are used by validators to verify block execution.
+ * Values stored in this contract are used by validators to verify BTC block execution.
  * The primary values used here are the Bitcoin block height and trailing block hash.
  */
 contract SovaL1Block is ISovaL1Block, Ownable {
     uint64 private currentBlockHeight;
     bytes32 private blockHashSixBlocksBack;
     uint256 private lastUpdatedBlock;
 
-    address private constant SYSTEM_ACCOUNT_ADDRESS = 0xDeaDDEaDDeAdDeAdDEAdDEaddeAddEAdDEAd0001;
-
     constructor() Ownable() {
         _initializeOwner(msg.sender);
     }
 
     function version() external pure virtual returns (string memory) {
-        return "0.1.0-beta.1";
+        return "0.1.0-beta.2";
     }
 
     function setBitcoinBlockData(uint64 _blockHeight, bytes32 _blockHash) external {

src/lib/SovaBitcoin.sol

@@ -12,7 +12,6 @@ library SovaBitcoin {
     address public constant BROADCAST_TRANSACTION_PRECOMPILE_ADDRESS = address(0x999);
     address public constant DECODE_TRANSACTION_PRECOMPILE_ADDRESS = address(0x998);
     address public constant CONVERT_ADDRESS_PRECOMPILE_ADDRESS = address(0x997);
-    address public constant VAULT_SPEND_PRECOMPILE_ADDRESS = address(0x996);
 
     /// @notice Bitcoin context contract address
     address public constant SOVA_L1_BLOCK_ADDRESS = 0x2100000000000000000000000000000000000015;
@@ -46,9 +45,9 @@ library SovaBitcoin {
     error InsufficientInput();
     error InvalidLocktime();
 
-    /// @custom:semver 0.1.0-beta.1
+    /// @custom:semver 0.1.0-beta.2
     function version() public pure returns (string memory) {
-        return "0.1.0-beta.1";
+        return "0.1.0-beta.2";
     }
 
     /**