Allow the user to customize the reticle

[LukeSaward]

AMyHUD::ReticleMaterial is of type class UMaterialInterface, which contains a function called GetBaseMaterial(), which returns a pointer to class UMaterial.

To do this, we could either set the Canvas size by searching for the instanced UCanvas/Canvas class within refunct-tas, or we could hook AHUD::DrawMaterial(), check whether the material is AMyHUD::ReticleMaterial, and if it is, modify the ScreenW and ScreenH arguments to make it appear larger/smaller than it actually is.

Furthermore, the user could also be able to customize the color of the crosshair by using the UMaterial::BaseColor field (which is of type struct FColorMaterialInput, which contains the field Constant, which is of type struct FColor. FColor has four fields, all of type unsigned char, and are B, G, R, A).