add a Help button to the main interface

[mnaugle-tt]

this button should either:
A. open a new partial window that displays help info
B. send users to a github wiki page for help
C. use the javascipt library that @mostaphaRoudsari showed that I always forget what it is called to highlight different parts of the interface with helpful tips.

I am leading towards option A with a link to option B.

A would be fairly high level help:

1. Create a CSV file that is formatted like so: ..... (link to github wiki for all CSV rules)
2. Open CSV in the interface
3. Use the various sorting and brushing actions to explore (images would be good here)

[mostaphaRoudsari]

It's called intro.js > http://usablica.github.io/intro.js/ :)