SSP-1219 Add "notes exist" MAP icons

1) Plan-level notes exist - edit-existing-notes-large-glossy.png
2) Term-level notes exist - edit-existing-notes-small.png
3) Course-level notes exist - edit-existing-notes-large.png

Seems a bit backwards that the course-level icon would be small and
the term-level icon large, but that looks like how the UI is
currently organized. Hence my legend above. None of this is set in
stone, though, obviously.