add deprecated warning for deprecated events

lib/core/events.js

@@ -1,11 +1,32 @@
 var EventEmitter = require('events');
 
+function warnIfLegacy(eventName) {
+  const legacyEvents = ['abi-vanila', 'abi', 'abi-contracts-vanila', 'abi-vanila-deployment'];
+  if (legacyEvents.indexOf(eventName) >= 0) {
+    console.warn("this event is deprecated and will be removed in future versions: " + eventName);
+  }
+}
+
+const _on         = EventEmitter.prototype.on;
+const _setHandler = EventEmitter.prototype.setHandler;
+
+EventEmitter.prototype.on = function(requestName, cb) {
+  warnIfLegacy(requestName);
+  return _on.call(this, requestName, cb);
+};
+
+EventEmitter.prototype.setHandler = function(requestName, cb) {
+  warnIfLegacy(requestName);
+  return _setHandler.call(this, requestName, cb);
+};
+
 EventEmitter.prototype.request = function(requestName, cb) {
-  this.emit('request:' + requestName, cb);
+  warnIfLegacy(requestName);
+  return this.emit('request:' + requestName, cb);
 };
 
 EventEmitter.prototype.setCommandHandler = function(requestName, cb) {
-  this.on('request:' + requestName, function(_cb) {
+  return this.on('request:' + requestName, function(_cb) {
     cb.call(this, _cb);
   });
 };

test_app/config/contracts.json

@@ -1,7 +1,7 @@
 {
   "default": {
     "versions": {
-      "web3.js": "1.0.0",
+      "web3.js": "0.20.0",
       "solc": "0.4.11"
     },
     "deployment": {