User can now select which column to show in ETT

This is done by using the tablesaw project, available on GitHub.

The Javascript and CSS parts were added to the public folder in their respective
subfolders.

`application.html.erb` was modified to include those extra javascript/css part
into the html template.

https://github.com/filamentgroup/tablesaw
Merge pull request #136 from thescouser89/table_fanciness

Table fanciness