RPGMaker MV Game Engine 1.6.2.1

This is a set of updates based on RPGMaker MV 1.6.2 to use PixiJS 5.3.3

Features

Faster rendering
Case insensitive file loading to better support Linux/Android without having to change your scripts
With NW.js v0.45.6 plays webm (VP8/VP9) files properly
Filter change for Pixi-Picture to get it to run properly (Issue submitted waiting for a real fix)
Added more keys in the keymap for easier use in scripts
Fixes to documentation, spelling, and javascript syntax
Added jshint information

ShaderTilemap is not working properly falling back on Tilemap
- Doesn't seem to be affecting performance
Plugins the load files directly or override the functions which load from disk may fail in case sensitive environments
- Wrap the file path with CS_URL.MapURL() to ensure it resolves to the correct case sensitive name
Overrides or calls to refereshVehicles will fail
- Use refreshVehicles instead
Overrides or calls to updateButtonsVisiblity will fail
- Use updateButtonsVisibility instead

Cleanup of Javascript (using let/const)
Add updates to plugins
Investigate if garbage collection needs to run (possibly do this during scene changes)
Check for any memory leaks
Submit issue against Pixi-Tilemap for the rendering issue
Submit issue against NW.js for performance issues starting with v0.46
Bring in proper filter fix for Pixi-Picture when it is released