Release 1.9.0: this version adds support for using the minecraft-heads.com categories as predefined categories. This was needed, because the custom search broke down after a change to that website. The owner of that website made me aware of a REST api that the website provides. It is for now limited to providing categorized heads, but he said that he is planning to provide a more extensive api after his website updates.
Sadly this means that getHeads using the MinecraftHeadsLoader will no longer be available, but fortunately you get access to the following categories from minecraft-heads.com: mh-alphabet, mh-animals, mh-blocks, mh-decoration, mh-food-drinks, mh-humans, mh-humanoid, mh-miscellaneous, mh-monsters and mh-plants.
Furthermore, I now started to put the category cache files in a subfolder called 'cache'. This makes it way easier to find the config files in the plugin/HeadsPluginAPI folder.
For all previously mentioned changes I needed to make quite some changes to both the categories.yml and config.yml. While all changes are backwards compatible (I think), it would have meant that some config values would be missing or changed, causing the new features to be nonfunctional.
For that reason
I changed the plugin so that when a new version is released, it will change the config to the new default.This means that any changes you made to config.yml or categories.yml need to be
backed up before updating the plugin and re-added what you need from the config files after the update! You most likely only changed categories.yml if you added extra custom categories. And you probably only changed config.yml if you changed the timeout for connecting to the databases.