UI: Remove "Lorem ipsum" below images on Edu/Rsrch

* (closes #298)
UI: Replace image for "histograms"

* (closes #299)
UI: introduces "Export" modal/popup

* (addresses #303 , #304)
collection: lighter black on "more" button

* (addresses #293)
UI: FIX OL broken on "physics" page

* (closes #309)