Take markers better distinguishable from stretch markers

[juliansader]

At present, take markers and stretch markers look almost indistinguishable, both being small diamonds, and their respective text and slope info are written on top of each other at the vertical middle of the media item.

Any tweaks to make take markers and stretch markers easier to distinguish and easier to target with the mouse would be welcome. Perhaps take markers (or their text, at least) can be moved up a bit, and their shape can be squares or circles.