make the '+' symbol be a spinning while the page is loading the sessions info

[ijiraq]

Currently the icon is a greyed '+' that becomes bright to indicate that the page is ready, but it doesn't show activity. Making the icon a spinning one would indicate the page is loading info.

[brianmajor]

Hey @ijiraq. I'm going to move this over to the 'science-portal' repository.

[hjeeves]

v 3.0 of the portal released last week has one solution to this problem. There are placeholders now that should pulse a bit while the session list and launch form are loading.

A wheel could still be added if this isn't enough. What do you think @ijiraq ?