Custom Loading Screen

Bug Fixes:

• Fixed incorrect usage of OpenGL, causing "OpenGL Error 1280 GL_INVALID_ENUM" error messages to be generated.
• Fixed the texture deletion system somtimes turning itself off, leading to out-of-memory errors.
  • This generally only happened when using slideshows with thousands of images (like for videos)

Add a texture expiry timer defaulting to 10 seconds.

This stops slideshows with 100s of images from consuming many GB of RAM to store all images, even long after they've been shown.

Not the first version for 1.12.2, but a fairly stable and mostly feature-complete one.

This project used to be called Better Loading Screen (on curseforge), before it was renamed to be "Custom Loading Screen" to better reflect the mod.