[FEATURE] Add redirectives to hscript

[NotHyper-474]

Wat dis do?

Adds a define, POLYMOD_REDIRECT_HSCRIPT that when enabled will redirect imports to hscript to the internal implementation of Polymod. This can be useful, for instance, to allow the HaxeFlixel Debugger console to work without the need of having hscript installed.

Note

Building may break in the future the more the classes are merged together.

[EliteMasterEric]

This is pretty neat, but if you install Polymod and don't have POLYMOD_REDIRECT_HSCRIPT enabled you get errors that make projects fail to build.

[NotHyper-474]

Finally got around to fix that as well, the issue was that you had hscript installed and Polymod was shadowing its files, so I had to scrap the original idea and replace it with a macro instead.

The way it works is quite clever, we just ask Haxe to give us the references that lead to a missing hscript type and replace those with a typedef to a Polymod type. I have to thank Context.onTypeNotFound for even allowing this to be possible.