Removed frivolous imports to improve readability

contracts/staking/contracts/src/fees/MixinExchangeFees.sol

@@ -45,8 +45,6 @@ import "./MixinExchangeManager.sol";
 /// monopolize a single pool that they all delegate to.
 contract MixinExchangeFees is
     IStakingEvents,
-    MixinDeploymentConstants,
-    Ownable,
     MixinConstants,
     MixinStorage,
     MixinZrxVault,

contracts/staking/contracts/src/fees/MixinExchangeManager.sol

@@ -32,7 +32,6 @@ import "../immutable/MixinStorage.sol";
 contract MixinExchangeManager is
     IStakingEvents,
     MixinDeploymentConstants,
-    Ownable,
     MixinConstants,
     MixinStorage
 {

contracts/staking/contracts/src/stake/MixinStake.sol

@@ -35,14 +35,9 @@ import "./MixinStakeStorage.sol";
 /// @dev This mixin contains logic for managing ZRX tokens and Stake.
 contract MixinStake is
     IStakingEvents,
-    MixinDeploymentConstants,
-    Ownable,
     MixinConstants,
     MixinStorage,
-    MixinZrxVault,
     MixinScheduler,
-    MixinStakingPoolRewardVault,
-    MixinStakeStorage,
     MixinStakeBalances,
     MixinStakingPoolRewards
 {

contracts/staking/contracts/src/stake/MixinStakeBalances.sol

@@ -32,8 +32,6 @@ import "./MixinStakeStorage.sol";
 /// **** Read MixinStake before continuing ****
 contract MixinStakeBalances is
     IStakingEvents,
-    MixinDeploymentConstants,
-    Ownable,
     MixinConstants,
     MixinStorage,
     MixinZrxVault,

contracts/staking/contracts/src/stake/MixinStakeStorage.sol

@@ -30,11 +30,8 @@ import "./MixinZrxVault.sol";
 /// @dev This mixin contains logic for managing stake storage.
 contract MixinStakeStorage is
     IStakingEvents,
-    MixinDeploymentConstants,
-    Ownable,
     MixinConstants,
     MixinStorage,
-    MixinZrxVault,
     MixinScheduler
 {
 

contracts/staking/contracts/src/stake/MixinZrxVault.sol

@@ -25,8 +25,6 @@ import "../immutable/MixinStorage.sol";
 /// @dev This mixin contains logic for managing and interfacing with the Zrx Vault.
 /// (see vaults/ZrxVault.sol).
 contract MixinZrxVault is
-    MixinDeploymentConstants,
-    Ownable,
     MixinConstants,
     MixinStorage
 {

contracts/staking/contracts/src/staking_pools/MixinEthVault.sol

@@ -27,8 +27,6 @@ import "../immutable/MixinStorage.sol";
 /// (see vaults/EthVault.sol).
 contract MixinEthVault is
     IStakingEvents,
-    MixinDeploymentConstants,
-    Ownable,
     MixinConstants,
     MixinStorage
 {

contracts/staking/contracts/src/staking_pools/MixinStakingPool.sol

@@ -58,15 +58,8 @@ import "./MixinStakingPoolRewards.sol";
 /// 3. Leverage the staking power of others by convincing them to delegate to your pool.
 contract MixinStakingPool is
     IStakingEvents,
-    MixinDeploymentConstants,
-    Ownable,
     MixinConstants,
     MixinStorage,
-    MixinZrxVault,
-    MixinScheduler,
-    MixinStakingPoolRewardVault,
-    MixinStakeStorage,
-    MixinStakeBalances,
     MixinStakingPoolRewards
 {
     using LibSafeMath for uint256;

contracts/staking/contracts/src/staking_pools/MixinStakingPoolRewardVault.sol

@@ -29,9 +29,6 @@ import "../libs/LibStakingRichErrors.sol";
 /// from within this contract.
 contract MixinStakingPoolRewardVault is
     IStakingEvents,
-    MixinDeploymentConstants,
-    Ownable,
-    MixinConstants,
     MixinStorage
 {
 

contracts/staking/contracts/src/staking_pools/MixinStakingPoolRewards.sol

@@ -29,14 +29,10 @@ import "./MixinStakingPoolRewardVault.sol";
 
 contract MixinStakingPoolRewards is
     IStakingEvents,
-    MixinDeploymentConstants,
-    Ownable,
     MixinConstants,
     MixinStorage,
-    MixinZrxVault,
     MixinScheduler,
     MixinStakingPoolRewardVault,
-    MixinStakeStorage,
     MixinStakeBalances
 {
 

contracts/staking/contracts/src/sys/MixinScheduler.sol

@@ -35,8 +35,6 @@ import "../interfaces/IStakingEvents.sol";
 /// and consistent scheduling metric than time. TimeLocks, for example, are measured in epochs.
 contract MixinScheduler is
     IStakingEvents,
-    MixinDeploymentConstants,
-    Ownable,
     MixinConstants,
     MixinStorage
 {

contracts/staking/contracts/src/vaults/EthVault.sol

@@ -25,9 +25,7 @@ import "./MixinVaultCore.sol";
 
 /// @dev This vault manages ETH.
 contract EthVault is
-    Authorizable,
     IEthVault,
-    IVaultCore,
     MixinVaultCore
 {
 

contracts/staking/contracts/src/vaults/StakingPoolRewardVault.sol

@@ -39,10 +39,7 @@ import "../immutable/MixinConstants.sol";
 /// When in Catastrophic Failure Mode, the Staking contract can still
 /// perform withdrawals on behalf of its users.
 contract StakingPoolRewardVault is
-    Authorizable,
     IStakingPoolRewardVault,
-    IVaultCore,
-    MixinDeploymentConstants,
     MixinConstants,
     MixinVaultCore
 {

contracts/staking/contracts/src/vaults/ZrxVault.sol

@@ -34,8 +34,6 @@ import "./MixinVaultCore.sol";
 /// failure mode, it cannot be returned to normal mode; this prevents
 /// corruption of related state in the staking contract.
 contract ZrxVault is
-    Authorizable,
-    IVaultCore,
     IZrxVault,
     MixinVaultCore
 {
@@ -160,7 +158,7 @@ contract ZrxVault is
 
         // notify
         emit ZrxWithdrawnFromVault(msg.sender, owner, amount);
-        
+
         // withdraw ZRX to owner
         zrxToken.transfer(
             owner,

contracts/staking/contracts/test/TestStorageLayout.sol

@@ -25,9 +25,6 @@ import "../src/interfaces/IStructs.sol";
 
 
 contract TestStorageLayout is
-    MixinDeploymentConstants,
-    Ownable,
-    MixinConstants,
     MixinStorage
 {
     function assertExpectedStorageLayout()