Add yax_start_at_min option and yax_end_at_max option

[ryanphung]

Thanks for building such a great tool; I love how everything is so simple and looks great.

This is a feature request. When I enable the option min_y_from_data, I notice that sometimes the y-axis marker doesn't start from the bottom and doesn't end at the top of the axis; hence there are large gaps.

There are options to change this behaviour for the x-axis (xax_start_at_min, and xax_end_at_max is being worked on in #456); but I cannot find similar options for y-axis.

[almossawi]

Thanks for the feature request. We'll be redoing the way axes work starting next month (see #489), which we're planning to dedicate to the 2.7 release. That will do away with the need to have separate options to extend the axes and ought to make things a lot clearer.

[ryanphung]

Hi @almossawi, thank you for the update.

[almossawi]

Being tracked in #456 and #489, so I'll close this, if you don't mind.