Allowance module: Refactor Safe interface from GnosisSafe to Safe (#489)

This PR:
- Renames the `GnosisSafe` interface to just `Safe`

modules/allowances/contracts/AllowanceModule.sol

@@ -4,7 +4,7 @@ pragma solidity >=0.7.0 <0.8.0;
 import "./Enum.sol";
 import "./SignatureDecoder.sol";
 
-interface GnosisSafe {
+interface ISafe {
     /// @dev Allows a Module to execute a Safe transaction without any further confirmations.
     /// @param to Destination address of module transaction.
     /// @param value Ether value of module transaction.
@@ -150,7 +150,7 @@ contract AllowanceModule is SignatureDecoder {
     /// @param delegate Delegate whose allowance should be updated.
     /// @param signature Signature generated by the delegate to authorize the transfer.
     function executeAllowanceTransfer(
-        GnosisSafe safe,
+        ISafe safe,
         address token,
         address payable to,
         uint96 amount,
@@ -239,7 +239,7 @@ contract AllowanceModule is SignatureDecoder {
         return keccak256(generateTransferHashData(safe, token, to, amount, paymentToken, payment, nonce));
     }
 
-    function checkSignature(address expectedDelegate, bytes memory signature, bytes memory transferHashData, GnosisSafe safe) private view {
+    function checkSignature(address expectedDelegate, bytes memory signature, bytes memory transferHashData, ISafe safe) private view {
         address signer = recoverSignature(signature, transferHashData);
         require(
             expectedDelegate == signer && delegates[address(safe)][uint48(signer)].delegate == signer,
@@ -261,7 +261,7 @@ contract AllowanceModule is SignatureDecoder {
         if (v == 0) {
             revert("Contract signatures are not supported by this module");
         } else if (v == 1) {
-            // If v is 1 we also use msg.sender, this is so that we are compatible to the GnosisSafe signature scheme
+            // If v is 1 we also use msg.sender, this is so that we are compatible to the Safe signature scheme
             owner = msg.sender;
         } else if (v > 30) {
             // To support eth_sign and similar we adjust v and hash the transferHashData with the Ethereum message prefix before applying ecrecover
@@ -274,7 +274,7 @@ contract AllowanceModule is SignatureDecoder {
         require(owner != address(0), "owner != address(0)");
     }
 
-    function transfer(GnosisSafe safe, address token, address payable to, uint96 amount) private {
+    function transfer(ISafe safe, address token, address payable to, uint96 amount) private {
         if (token == address(0)) {
             // solium-disable-next-line security/no-send
             require(safe.execTransactionFromModule(to, amount, "", Enum.Operation.Call), "Could not execute ether transfer");