Falsy Data Quicktests

Please comment on:

more cases that could to be added
code quality
style
the way Im doing things
etc.

Currently these quicktests render null, NaN, undefined, false, and empty string data on linear, ordinal, and time scales. All data points have y values as 1.

thanks peeps

screenshots here:

![screen shot 2014-09-30 at 8 20 30 pm](https://cloud.githubusercontent.com/assets/8551049/4469827/fd2920ca-4919-11e4-88f4-ac10daf6e15f.png)
![screen shot 2014-09-30 at 8 20 38 pm](https://cloud.githubusercontent.com/assets/8551049/4469826/fd219030-4919-11e4-815a-897cdf6b914d.png)
![screen shot 2014-09-30 at 8 20 47 pm](https://cloud.githubusercontent.com/assets/8551049/4469825/fd215f98-4919-11e4-8958-82fba8bfa44f.png)
![screen shot 2014-09-30 at 8 21 54 pm](https://cloud.githubusercontent.com/assets/8551049/4469836/2611b088-491a-11e4-907f-59300d05f7f4.png)