Assign property to group headers to make them disappear when filterin…

[dassburger]

Bug fixes for empty group header hiding when filtering agenda view:

• Assign org-super-agenda-header property to the group header and the newline before it, so that when filtering agenda view, both the header and it's newline are hidden too. (org-super-agenda--hide-or-show-groups expects that property).
• Assign org-super-agenda-header property to the new line before the group header, so that calendar view does not have extra newlines inside it when filtering.
• Preserve agenda block separators when hiding groups.

[AndreaOrru]

Any chance this will be merged?

[alphapapa]

@AndreaOrru Probably, I just have to find time to review it carefully, since the diff is rather large (though largely indentation due to the enclosing let, it seems). Feel free to test it and report back. :)

[alphapapa]

Thanks for your patience. Please see this suggested change.

[alphapapa]

It should be possible to use looking-at-p for this test, which would save consing a string.