Add descriptions for each of the NMF options

[naikai]

Maybe try using shinyBS

http://stackoverflow.com/questions/32226331/r-shiny-pop-up-window-with-options

http://stackoverflow.com/questions/33925430/shiny-plot-results-in-popup-window

http://stackoverflow.com/questions/31107645/shiny-how-to-create-a-confirm-dialog-box

[naikai]

Done using bsTooltip from shinyBS