rFXGen v4.2

Official release for rFXGen v4.2. Some features on this release:

• ADDED: Issue report window
• ADDED: Support splash screen
• REMOVED: Sponsors window
• REVIEWED: Main toolbar and help window
• REVIEWED: About window sponsor button
• UPDATED: Using raylib 5.1-dev and raygui 4.1-dev
• UPDATED: Using tinyfiledialogs 3.18

Enjoy rFXGen!