Eomaps

new
- `add_marker()` function added to manually add markers
- `add_annotations()` function added to manually add annotations
- annotate can now be used on multiple buttons
- add `text` argument to `m.cb.annotate` to manually specify the text
- add `m.cb.clear_annotations()` function to delete annotations
- add `savefig` function to save the image
fixes
- fix permanent annotations
- + more fixes + more unittests

new
- allow multiple callbacks of the same function (using different mouse-button assignments)
- add option to make annotations permanent `m.cb.annotate(... , permanent=True)`
- add option to format annotation display via `m.cb.annotate(..., val_fmt=<callable>)`
- add `m.cb.mark` callback (e.g. to overlay markers around selected points)
- all callback-returns are now accessible via `m.cb...`
- add `m.cb.cb_list` (e.g. a hardcoded list of available callback functions)
fixes
- better fetching of background for blitting (now also works with multiple callbacks)

This is a first (beta) release... use with care!