Cgeo: Support new gc.com attributes

[Lineflyer]

Just released today, no technical info yet:

https://forums.geocaching.com/GC/index.php?/topic/358304-release-notes-new-attributes-august-31-2020/

There are 4 new atrributes..which are IMHO indeed useful:

• Bonus cache
• Power trail
• Challenge cache
• Solution checker available

I will next days apply the attributes to my matching owned cache (AFAIR I have all of them) to allow testing.

[Lineflyer]

Attribute already added...couldn't resist:

• https://coord.info/GC3RG33 --> Challenge attribute
• https://coord.info/GC8X9BQ --> Bonus cache
• https://coord.info/GC5HQ2Z --> Power trail (well, a small one)

The solution checker attribute should either show up automatically or I need to re-edit the cache..not sure, what the release note means:

• https://coord.info/GC3EQ4W --> Solution checker attribute

[Narrat]

The solution checker attribute will only be added automatically if you use the gc.com checker itself. External checkers won't be covered by that. And they will add it for everyone via a script. But of course owner can add it themselves if they want to and before the auto add has run

[bekuno]

Codewise the changes are prepared.
But now we need fine icons.

My favorites are

• Challenge cache: https://thenounproject.com/term/challenge/3203889/
• Bonus cache: https://thenounproject.com/term/add/2640238/
• Power trail stage: https://thenounproject.com/term/trail/689645/
• GC Solution checker: https://thenounproject.com/term/solution/2998552/

Alle 4 are licensed by Creative Commons, esp. CCBY
(When using it for any project, you are required to give credit to the icon‘s creator or purchase a royalty–free license.)

What do you mean?

Does someone has ressources to prepare the icons for c:geo?
Informations are stored in main/project/attributes.
The readme.txt is a bit outdated but should sufficient to built the icons in a Linux environment (Points 1-4).

[Lineflyer]

We are already using icons from this source and have it referenced in About c:geo.

Those you suggested look quite good for their respective meaning.

[bekuno]

This would be the icons and the English texts