javascript block

**let's change all of the keys in a timeseries to some other key**
![screen shot 2014-04-27 at 6 35 30 pm](https://cloud.githubusercontent.com/assets/597897/2812483/ae34ef4a-ce5c-11e3-9271-2515023c623f.png)

**let's use JS to complete an HTTP request**
![screen shot 2014-04-27 at 6 26 53 pm](https://cloud.githubusercontent.com/assets/597897/2812484/b0ce723a-ce5c-11e3-8bd0-311b0e779260.png)

**small example of _some_ inbuilt functions...**
![screen shot 2014-04-27 at 7 31 23 pm](https://cloud.githubusercontent.com/assets/597897/2812597/1f92e9d8-ce64-11e3-9bf4-6c9a99d5ca40.png)


adds support for javascript modification of messages. streamtools: now with array modification! includes http://underscorejs.org/. JS implementation care of https://github.com/robertkrimen/otto