Config-related deprecation messages are thrown by Anki

[jthulhu]

Problem description

Apparently, Anki has changed its API and is deprecating one that is still used in this add-on.
The messages are

• conf key heatmap should be fetched with col.get_config(), and saved with col.set_config()
• named arguments in queries will go away in the future:, followed by the SQL query that triggers the warning.

There are other (very minor) deprecation warnings, but I have opened #134 to fix them.

Checklist

Please replace the space inside the brackets with an x if the following items apply:

• I've verified that I use the latest version of the add-on by redownloading it from AnkiWeb
• I've verified that I use the latest version of Anki by checking at https://apps.ankiweb.net#download
• I've checked if anyone else reported this problem before by looking through the issue reports. I also checked to see if there is a section about known issues in the add-on description, documentation, or README.

I have removed sections that were not pertinent from the default template.

[glutanimate]

Thanks for the report! The config warnings are still present. Will look into that, but have to be a bit careful as that's fairly ancient libaddon code and somewhat fickle. (Hoping to refactor this sooner rather than later)