Make collision code placement more like original (+ small fixes)

# Conflicts:
#	premake5.lua
#	src/CMakeLists.txt
#	src/collision/Collision.cpp
#	src/core/Collision.h

src/collision/ColSphere.h

@@ -0,0 +1,21 @@
+#pragma once
+
+#include "SurfaceTable.h"
+
+struct CSphere
+{
+	// NB: this has to be compatible with a CVuVector
+	CVector center;
+	float radius;
+	void Set(float radius, const CVector &center) { this->center = center; this->radius = radius; }
+};
+
+struct CColSphere : public CSphere
+{
+	uint8 surface;
+	uint8 piece;
+
+	void Set(float radius, const CVector &center, uint8 surf, uint8 piece);
+	bool IntersectRay(CVector const &from, CVector const &dir, CVector &entry, CVector &exit);
+	using CSphere::Set;
+};