runCode: Add memoryWordCount to the step event object.

If a user modifies memory like shrinking and growing,
he also needs access to this property to reflect memory size changes.

Author: pinkiebell

lib/runCode.js

@@ -152,7 +152,8 @@ module.exports = function (opts, cb) {
         address: runState.address,
         account: runState.contract,
         stateManager: runState.stateManager,
-        memory: runState.memory
+        memory: runState.memory,
+        memoryWordCount: runState.memoryWordCount
       }
       /**
        * The `step` event for trace output
@@ -167,6 +168,7 @@ module.exports = function (opts, cb) {
        * @property {Buffer} address the address of the `account`
        * @property {Number} depth the current number of calls deep the contract is
        * @property {Buffer} memory the memory of the VM as a `buffer`
+       * @property {BN} memoryWordCount current size of memory in words
        * @property {StateManager} stateManager a [`StateManager`](stateManager.md) instance (Beta API)
        */
       self.emit('step', eventObj, cb)