Fixing #89, #84,  #61 - download.txt to *Test.java for all browsers

* Supporting zoom and panning using d3's zoom behavior (minor change)
* Reversing table and graph view labels (minor fix)
* download.txt to *Test.java using Content-disposition : attachment header on the server side. Should work across all browsers as opposed to the data attribute. (Please check and confirm)

![screenshot from 2014-05-31 17 50 41](https://cloud.githubusercontent.com/assets/514557/3140543/cc0f80ea-e926-11e3-8923-1833cd5b1f2b.png)
![screenshot from 2014-05-31 17 50 26](https://cloud.githubusercontent.com/assets/514557/3140542/cc0f2f28-e926-11e3-8e6c-9a521f3ce5b2.png)