Made changes to deleting the container from list of containers in the session

Just searched through the list and did a splice at the location
In `for` loops, it is always preferable to use the following pattern unless you have a good reason:

````javascript
for (var i = 0; i < this.containers.length; i++) {
````

or even better

````javascript
var i; // explicitly set aside variable for future readability

for (i = 0; i < this.containers.length; i++) {
````

In JavaScript, there is a concept of enumeration vs iteration. It can lead to some nasty bugs that are hard to find. See http://stackoverflow.com/a/3010848 and https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/for...in for more information.

There are probably bad examples of this in the current codebase - they were probably committed during a moment of oversight or intoxication and should be removed :)