New Mode Template for Recent Processing Versions

[soir20]

Hello!

The Mode Overview wiki page in this repository currently links to an outdated mode template for Processing 2. There's another template that was created for 3.0 but breaks on versions since the Processing 3 alphas. Neither template has been updated in over six years.

I created an updated template that runs on the most recent Processing versions, including 3.5.4 and 4.0a6 (tested on Windows). Like the others, it extends Java mode. I fixed a few bugs in the previous templates. (Code completion and the debugger were broken because some files were not copied into the template mode.) I've also added more documentation about setting up and mode and instructions on how to import the mode template in IntelliJ.

I think it would be helpful for others to have a link to the updated template on the wiki page. It looks like editing the wiki is enabled here, so I can add that myself. However, I wanted to post an issue here to explain this change and in case anyone had any feedback for the template. (GitHub doesn't have pull requests for wikis or a feature to discuss wiki edits.)