0.1

Fork from FNA 20.11 for .NET Core 3.1

The following types have been deleted:

Point
Plane
Ray
BoundingFrustum
BoundingBox
BoundingSphere
ContainmentType
PlaneIntersectionType
Curve
CurveKey
CurveKeyCollection
CurveLoopType
CurveTangent
Model
ModelBone
ModelBoneCollection
ModelEffectCollection
ModelMesh
ModelMeshCollection
ModelMeshPart
ModelMeshPartCollection
GameComponent
DrawableGameComponent
GameComponentCollection
GameComponentCollectionEventArgs
IDrawable
IUpdateable
GameServiceContainer
IGraphicsDeviceManager
IGraphicsDeviceService

Modifications in response to the above-deleted types:

All code related to IDrawable, IUpdateble, GameComponent, DrawableGameComponent, GameComponentCollection, GameComponentCollectionEventArgs is removed in Game.
GraphicsDeviceManager is created as late as possible in the public constructor of Game.
Added static Instance field to GraphicsDeviceManager so the singleton can be accessed at any time.
ContentManager and ResourceContentManager now have zero constructor arguments.
The content pipeline no longer understands the deleted types.
The following types have been replaced with types in System.Numerics:

Vector2
Vector3
Vector4
Matrix -> Matrix4x4