chore: add ctoken and clean up interfaces

interfaces/aave/Aave.sol

@@ -1,8 +1,6 @@
 pragma solidity ^0.5.17;
 
 interface Aave {
-    function getRevision() internal pure returns (uint256);
-
     /**
      * @dev deposits The underlying asset into the reserve. A corresponding amount of the overlying asset (aTokens)
      * is minted.

interfaces/aave/LendingPoolAddressesProvider.sol

@@ -5,7 +5,7 @@ pragma solidity ^0.5.17;
 @notice provides the interface to fetch the LendingPoolCore address
  */
 
-contract ILendingPoolAddressesProvider {
+contract LendingPoolAddressesProvider {
     /**
      * @dev returns the address of the LendingPool proxy
      * @return the lending pool proxy address

interfaces/aave/Oracle.sol

@@ -1,16 +1,7 @@
 pragma solidity ^0.5.17;
 
-/************
-@title IPriceOracle interface
-@notice Interface for the Aave price oracle.*/
-interface IPriceOracle {
-    /***********
-    @dev returns the asset price in ETH
-     */
-    function getAssetPrice(address _asset) external view returns (uint256);
+interface Oracle {
+    function getAssetPrice(address reserve) external view returns (uint256);
 
-    /***********
-    @dev sets the asset price, in wei
-     */
-    function setAssetPrice(address _asset, uint256 _price) external;
+    function latestAnswer() external view returns (uint256);
 }

interfaces/compound/Token.sol

@@ -42,12 +42,6 @@ interface cToken {
      */
     function allowance(address owner, address spender) external view returns (uint256);
 
-    /**
-     * @dev Function to simply retrieve block number
-     *  This exists mainly for inheriting test contracts to stub this result.
-     */
-    function getBlockNumber() internal view returns (uint256);
-
     /**
      * @notice Returns the current per-block borrow interest rate for this cToken
      * @return The borrow interest rate per block, scaled by 1e18
@@ -118,7 +112,7 @@ interface cToken {
 
     /**
      * @notice Get the token balance of the `owner`
-     * @param owner The address of the account to query
+     * @param _owner The address of the account to query
      * @return The number of tokens owned by `owner`
      */
     function balanceOf(address _owner) external view returns (uint256);

interfaces/cream/CToken.sol

@@ -0,0 +1,27 @@
+// SPDX-License-Identifier: MIT
+
+pragma solidity ^0.5.17;
+
+interface CToken {
+    function decimals() external view returns (uint8);
+
+    function totalSupply() external view returns (uint256);
+
+    function underlying() external view returns (address);
+
+    function balanceOfUnderlying(address) external returns (uint256);
+
+    function supplyRatePerBlock() external returns (uint256);
+
+    function exchangeRateCurrent() external returns (uint256);
+
+    function mint(uint256) external returns (uint256);
+
+    function balanceOf(address) external view returns (uint256);
+
+    function redeemUnderlying(uint256) external returns (uint256);
+
+    function redeem(uint256) external returns (uint256);
+
+    function approve(address, uint256) external returns (bool);
+}

interfaces/cream/Controller.sol

@@ -2,6 +2,8 @@
 
 pragma solidity ^0.5.17;
 
+import "./CToken.sol";
+
 interface Creamtroller {
     /**
      * @notice Claim all the comp accrued by holder in all markets
@@ -29,5 +31,5 @@ interface Creamtroller {
      * @param cTokens The list of addresses of the cToken markets to be enabled
      * @return Success indicator for whether each corresponding market was entered
      */
-    function enterMarkets(address[] memory cTokens) public returns (uint256[] memory);
+    function enterMarkets(address[] calldata cTokens) external returns (uint256[] memory);
 }