[FIX] Tick-formatting for spharpy.plot.scatter

[hoyer-a]

Which issue(s) are closed by this pull request?

Closes #313

• make number of ticks adaptive
• use default of 10 bins for longest axis (matplotlib default), fall back to 1 bin if axis range is too small
• get number of ticks relative to tick spacing on longest axis
• create baseline plots

[ahms5]

Thank you for taking care. Have you recreate the baseline plots? I bet, sth would change there. I would also recomment to add a test, so that this woulnt happen again.

[mberz]

Hey @hoyer-a, I was wondering if there's any progress on this? If no I think I'd prepare the next bug release without this PR included. I feel that the bugfixes currently waiting to be released are more urgent than this one, so don't worry if you don't have the bandwidth to finalize this one at the moment.

[hoyer-a]

Not really, i made some progress with the tick locators and formatting but it's still no good solution.
I want to get something ready before friday, but if the bugfixes are really urgent i think this one can wait.

[mberz]

Looks good! Only have a tiny nitpick on the code to make it more readable.

Can you please add a history entry?

[mberz]

thanks!