Port MSCKF complete (from now)

LinearAlgebra/Matrix.cs

@@ -2,6 +2,7 @@ using System;
 using System.Diagnostics;
 using Vector3 = UnityEngine.Vector3;
 using Vector2 = UnityEngine.Vector2;
+using Quaternion = UnityEngine.Quaternion;
 
 public readonly struct Slice {
     public uint start { get; }
@@ -216,7 +217,7 @@ public class Matrix2 {
     public Matrix2 Slice(Slice rowRange, Slice colRange) {
         return Slice((rowRange.start, rowRange.stop), (colRange.start, colRange.stop));
     }
-    
+
     public Matrix2 Slice((uint start, uint stop) rowRange, (uint start, uint stop) colRange) {
         float[,] result = new float[rowRange.stop - rowRange.start, colRange.stop - colRange.start];
 
@@ -374,6 +375,15 @@ public class Matrix1 {
         return new Matrix1(result);
     }
 
+    public static Matrix1 FromQuaternion(Quaternion q) {
+                float[] result = new float[4];
+        result[0] = q.x;
+        result[1] = q.y;
+        result[2] = q.z;
+        result[3] = q.w;
+        return new Matrix1(result);
+    }
+
     public Vector2 vector2 {
         get {
             if (this.magnitude != 2)
@@ -388,6 +398,13 @@ public class Matrix1 {
             return new Vector3(this.data[0], this.data[1], this.data[2]);
         }
     }
+    public Quaternion quaternion {
+        get {
+            if (this.magnitude != 4)
+                throw new System.ArgumentException("Matrix1 must be of size 4");
+            return new Quaternion(this.data[0], this.data[1], this.data[2], this.data[3]);
+        }
+    }
 
     public Matrix2 Transpose() {
         float[,] r = new float[1, this.magnitude];