Update ethers.js to latest version v4

The main change is how ethers loads the networkId which is now async.
Thus the init process had to change a bit

lib/contracts/base.js

@@ -17,11 +17,7 @@ class Base {
   }
 
   on(type, callback) {
-    let eventMethod = `on${type.toLowerCase()}`;
-    // Don't use this.contract.events here. Seems to be a bug in ethers.js
-    this.contract[eventMethod] = callback;
-
-    return this;
+    return this.contract.on(type, callback);
   }
 }
 module.exports = Base;

lib/contracts/kernel.js

@@ -12,7 +12,9 @@ class Kernel extends Base {
   }
 
   appNamehash(appName) {
-    return AppIds[this.contract.provider.chainId.toString()][appName];
+    // actually provider.network is an asynchronous property.
+    // but when we call this function kredits is already initialized and the network is already loaded
+    return AppIds[this.contract.provider.network.chainId.toString()][appName];
   }
 }
 

lib/kredits.js

@@ -36,9 +36,7 @@ class Kredits {
 
     this.provider = provider;
     this.signer = signer;
-    // by default we only need the DAO/Kernel address.
-    // the rest is loaded from there in the init() function
-    this.addresses = addresses || { Kernel: DaoAddresses[this.provider.chainId.toString()] }; // chainID must be a string
+    this.addresses = addresses || {};
     this.abis = abis || ABIS;
     this.ipfs = new IPFS(ipfsConfig);
     this.contracts = {};
@@ -46,17 +44,20 @@ class Kredits {
 
   init(names) {
     let contractsToLoad = names || APP_CONTRACTS;
-    let addressPromises = contractsToLoad.map((contractName) => {
-      return this.Kernel.getApp(contractName).then((address) => {
-        this.addresses[contractName] = address;
-      }).catch((error) => {
-        console.log(error);
-        throw new Error(`Failed to get address for ${contractName} from DAO at ${this.Kernel.contract.address}
-          - ${error.message}`
-        );
+    return this.provider.getNetwork().then(network => {
+      this.addresses['Kernel'] = this.addresses['Kernel'] || DaoAddresses[network.chainId.toString()];
+      let addressPromises = contractsToLoad.map((contractName) => {
+        return this.Kernel.getApp(contractName).then((address) => {
+          this.addresses[contractName] = address;
+        }).catch((error) => {
+          console.log(error);
+          throw new Error(`Failed to get address for ${contractName} from DAO at ${this.Kernel.contract.address}
+            - ${error.message}`
+          );
+        });
       });
+      return RSVP.all(addressPromises).then(() => { return this });
     });
-    return RSVP.all(addressPromises).then(() => { return this });
   }
 
   static setup(provider, signer, ipfsConfig = null) {
@@ -82,7 +83,7 @@ class Kredits {
   }
 
   get Operator() {
-    return this.Proposal();
+    return this.Proposal;
   }
 
   get Token() {