Timer continued

This is a continuation of #505, updated for `bttf`. Sorry for the monster merge commit in there, apparently I don't know how to rebase :/. I'm still looking for a good alarm sound to play on completion of the timer.

![screenshot from 2014-06-01 20 32 01](https://cloud.githubusercontent.com/assets/4411471/3143224/f8501d5a-e9ed-11e3-96c2-70392eaafd7f.png)
![screenshot from 2014-06-01 20 32 53](https://cloud.githubusercontent.com/assets/4411471/3143225/f95f7308-e9ed-11e3-94bb-f119c91cd3b1.png)
![screenshot from 2014-06-01 20 33 37](https://cloud.githubusercontent.com/assets/4411471/3143226/fad91bf8-e9ed-11e3-8ba8-ccfec23b9b0a.png)
<img src="https://cloud.githubusercontent.com/assets/4411471/3143242/ab412080-e9ee-11e3-89db-bbff142e2784.PNG" width="250px" />

Not sure how I feel about the spacing in the mobile screenshot, though.

I think you can simplify this. Since we're only decrementing by 1 second, call `updateTimer` every 1 second

```js
setInterval(updateTimer, 1000);
```

And then `updateTimer` can just have this:

```js

function updateTimer(){
    time_left -= 1000;
    ...
```

With the old one you don't get the time left that you really want:
![screen shot 2014-06-13 at 10 14 51 am](https://cloud.githubusercontent.com/assets/81969/3270892/30c34b24-f305-11e3-8487-8bef73998b46.png)

But with this change you get:
![screen shot 2014-06-13 at 10 16 09 am](https://cloud.githubusercontent.com/assets/81969/3270906/4a8b1974-f305-11e3-9466-d0d74e50bfd7.png)